File Format and Extension of [filename] don’t Match in Excel File

Summary: The “File format and extension of [filename] don’t match. The file could be corrupted or unsafe” error message indicates that the Excel file you’re trying to open is unsupported, unsafe, or corrupted. Read this article to learn more about this error and how to fix this error. It also mentions an advanced Excel recovery tool to repair the corrupted Excel file and retrieve all its data in a few clicks.

You can encounter the “File format and extension of [filename] don’t match. The file could be corrupted or unsafe” error when the Excel application detects any issue with the file. This happens when you try to open an old version file format in a newer version or if the file is received from an unsafe destination. This can prevent you from opening the Excel file.

As indicated from the error message, this error occurs due to the following reasons:

• The file has incorrect file extension.
• The file is corrupted.
• The file you are trying to open is protected.

Now, let’s see how to resolve this Excel error.

Methods to Fix the “File format and extension of [filename] don’t match” Error

Try the following methods to troubleshoot the “File format and extension don’t match” error in Excel.

Method 1: Rename the Excel File

You can face the “File format and extension don’t match” issue if the file has incorrect extension. It can occur if the file extension has been altered or you’ve mistakenly saved the file with incorrect extension. To fix this, you can try renaming the Excel file with the correct file extension.  

Method 2: Check the Default Excel File Format

Different versions of Microsoft Excel use different default file formats. For example, .xls is the default file format of older versions (2003 and lower) of Excel, whereas .xlsx format is used by the newer versions (2007 and later). Opening the Excel file with an incompatible extension can cause the “File format and extension don’t match” issue. You can check the Excel version you are using and ensure it’s compatible with the Excel file you are trying to open.

Method 3: Change the Protected View Settings

You may receive the “File format and extension of excel don’t match” error if the Excel file is protected. You can check and try disabling the Protected View settings .  

Caution: Changing the Protected View settings can put your system at risk. If the Excel file is being downloaded from the internet, it may contain viruses that can infect your system. So be careful before disabling the Protected View settings.

Steps to Change Protected View Settings in Excel:

• In the Excel’s File menu, click on Options.
• Select Trust Center > Trust Center Settings.

• Under Trust Center, select Protected View and disable the below three options:
• Enable Protected View for files originating from the internet.
• Enable Protected View for files located in potentially unsafe locations.
• Enable Protected View for Outlook attachments.

• Click OK. Then, try to open the Excel file.

Method 4: Check and Provide the Excel File Permissions

Sometimes, you can get the error if you don’t have sufficient permissions to open the Excel file. This usually happens when you try to open the Excel file received from other sources. You can check and provide the desired permissions to fix the error. Here are the steps:

• Locate the affected Excel file, right-click on it, and select Properties.

• In the Properties window, click the Securities option and select Edit.

• In the Security window, under ‘Group or users name’, select the user names. Check the file permissions and make sure Full Control is enabled. If not, then click on the Add option.

• Click on the Advanced option in the Users, Computers, Service Accounts, or Groups window**.**

• Click the Find Now option. A list of all users and groups appears in the search field.

• Select “Everyone” from the list and then click OK.

• In the object names field, you will see ‘Everyone’. Click on OK.

• In the Permissions window, select “Everyone” and enable all options (Full Control, Modify, Read & Execute, Read, and Write) under Permissions for Everyone.

• Click Apply and then OK.

Method 4: Repair your Excel File

As the error message indicates, corruption is one of the causes of the “File format and extension of [filename] don’t match” error. If your file is corrupted, you can repair it using Microsoft’s built-in Open and Repair tool. Here are the steps to run the Open and Repair tool to repair corrupted Excel file:

• In Excel, click on File.
• Click Open and then click on Browse to select the corrupted Excel file.
• In the Open dialog box, click the Excel workbook (in which you are facing the error).
• Click the arrow next to the Open button and select Open and Repair.
• Then, click Repair to recover as much data as possible.
• The Excel prompts a message after the repair process is complete. Click Close.

The Open and Repair utility may fail to give the intended results. In such a case, you can repair the corrupted/damaged Excel file using a specialized Excel repair tool . Stellar Repair for Excel is one such tool that can repair severely corrupted Excel files. With the help of this tool, you can quickly recover all the objects from the Excel file. The tool has a simple user interface that even a non-technical can use to repair the Excel files. The tool can also repair multiple Excel files at once. You can check the tool’s functionality by downloading its demo version.

Closure

You can encounter the “File format and extension of [filename] don’t match” error due to different reasons. To resolve the issue, you can check the file extension, permissions, protected settings, etc. If you suspect the error has occurred due to corruption in the Excel file, you can try repairing the Excel file using the Open and Repair tool. If nothing works for you, then try Stellar Repair for Excel . It can repair highly damaged Excel files and recover all the data while preserving the file properties and cell formatting. The tool can help you fix all the common corruption-related errors quickly.

Top 5 Ways to Fix Excel File Not Opening Error

Summary: MS Excel users sometimes face issues while using the MS Excel application. One such issue is the Excel file not opening error. In this post, we’ve mentioned the reasons that may result in this error and the ways to resolve it. Also, you’ll find about an Excel repair software that can help you repair corrupt Excel files.

Several Microsoft Excel users have reported encountering the ‘Excel file not opening’ error when opening their Excel file. There are several reasons that may cause this error. In this post, we’ll be discussing the reasons that may lead to the ‘Excel file not opening’ error and the top 5 ways to fix this error.

Why Does the ‘Excel File Not Opening’ Error Appear?

Following are some possible causes that may result in the ‘Excel file not opening’ error:

1. There may be a problem with an add-in that is preventing you from opening the Excel files.
2. There’s a chance that your Excel application is faulty.
3. Your Excel program is unable to communicate with other programs or the operating system.
4. The file association might have been broken. This is a common problem faced by users who have upgraded their Excel application or operating system.
5. The file you’re trying to open is corrupted.

5 Ways to Fix Excel File Not Opening Error

Let’s explore the ways to resolve the Excel file not opening error:

1. Uncheck the Ignore DDE Checkbox

Dynamic Data Exchange (DDE)allows Excel to communicate with other programs. The Excel error may occur due to incorrect DDE settings. You need to ensure that the correct DDE configuration is enabled. Follow the steps provided below:

• Launch your MS Excel file.
• Go to File > Options.

• Now click on Advanced.

• Further, find the General option on the screen.

• Uncheck the option **‘Ignore other applications that use Dynamic Data Exchange (DDE)**’.
• Click OK to save the changes.

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When you launch your Excel file, the file association ensures that the Excel application is used to open the file. You can try to reset these associations and see if Excel opens after this. Proceed with the following steps to do so:

• Navigate to Start Menu and launch Control Panel.
• Now, navigate to Programs > Default Programs > Set Your Default Programs.

• A new window will open. Herein, find the Excel program in the list and select it. Now, select the option ‘Choose defaults for this program’. Click OK.

• A new window for ‘Set Program Associations’ will open.
• Check the box against the ‘Select All’ option.
• Further, click Save to reset the Excel File Associations settings.

3. Disable Add-Ins

Many people install third-party add-ins to enhance the application’s functionality. Sometimes, these add-ins can create an issue. Follow the below-mentioned steps to disable the problem creating add-ins:

• Launch MS Excel application.
• Navigate to File > Options > Add-ins.

• In the window that opens, go to the Manage option at the bottom.
• Herein, select the COM Add-ins option from the dropdown list. Click Go.

• In the COM Add-ins window, uncheck all the boxes to disable the add-ins. Click OK.

4. Repair MS Office Program

Sometimes the issue is not with your Excel file. Instead, the reason for the error can be a corrupt MS Office application. You can repair the program to fix the Excel file not opening error. Here are the steps:

• Press the Windows + R keys to launch the ‘Run’ dialog box.

• Enter the text ‘appwiz.cpl’ to launch the program and features window.

• Find the MS Office program in the list of applications.

• Right-click on it and select Change.

• In the new window, select the Quick Repair radio button. Click Repair.

• Follow the on-screen instructions to repair the Office application. Once the repair process is completed, you can try opening the Excel file to see if the problem is resolved.

5. Disable Hardware Graphics Acceleration

The hardware graphics acceleration assists in the system’s better performance, especially when you use MS Office applications, like MS Excel or Word. Sometimes, this causes the Excel file not opening issue. You can disable this option to try to resolve the issue. Here are the steps:

• Launch your MS Excel application.
• Navigate to File > Options > Advanced.
• Herein, go to the Display option.
• Uncheck the Disable hardware graphics acceleration checkbox. Click OK.

What If These Solutions Do Not Work?

If you have applied all the methods mentioned above and still cannot open your Excel file, there are chances that your file is corrupted. You can use a specialized Excel repair tool , such as Stellar Repair for Excel to repair the corrupted Excel file. This software has powerful algorithms that can scan and repair even severely corrupt Excel files, without any file size limitation. After repairing the file, it restores all the data, including tables, charts, rules, etc. to a new Excel, with 100% integrity.

To know how the software works, see the video below:

Conclusion

Before you proceed with resolving the Excel file not opening error, try to find out the root cause of this error. If you know the real reason, you can try the method right away. If the reason for the error is corruption in the Excel file, the best option is to repair the file using a professional Excel repair tool, such as Stellar Repair for Excel .

Simple ways to Open Corrupt Excel file Without any Backup

Summary: The blog describes simple ways to open corrupt Excel file without any backup. It explains some manual workarounds that you can try to open the file. Also, it mentions about an Excel file repair tool that can quickly fix the corrupt file and recover data from it.

Do you have an Excel file that does not open because of corruption issue? And every time you try to open it, an error message ‘the file is corrupt and cannot be opened’ pops-up?

Excel File Corruption Message

Also, you don’t have a healthy backup of the Excel file to restore the data? If so, you can try repairing the corrupt file by using a few simple yet effective manual workarounds mentioned below.

How to Open a Corrupt Excel File without Backup?

Following are some manual methods that can help you open a corrupt Excel file:

Method 1: Repair Corrupt Excel File

When attempting to open a corrupt file, Excel automatically starts ‘File Recovery’ mode to repair the file. But, if the recovery mode doesn’t start, try Microsoft Excel’s built-in ‘Open and Repair’ feature to manually repair the file.

To use this feature, perform the following steps:

Step 1: Open a Blank workbook in Excel, and then click File > Open.

Step 2: In the Open window, browse and select the corrupt file.

Step 3: Click the arrow that is beside the Open tab, and select Open and Repair.

Open and Repair Option

Step 4: Implement one of the following:

• Click the Repair button. (This is to recover as much data as possible.)
• Click the Extract Data button. (This is to recover values and formulas from the Excel file if the repair process fails to recover the entire data.)

Excel Built-in Repair Options

If using Open and Repair does not work , move to the next method.

Method 2: Disable the Protected View Feature

Some Excel users have reported that turning off the ‘protected view’ feature in Excel helped them open the corrupt file. You can also try to disable this feature and open the file. To do so, follow these steps:

Step 1: Open a blank Excel file, click on File > Options.

Step 2: In the Excel Options window, select Trust Center, and then click Trust Center Settings.

Excel Trust Center Settings

Step 3: Click OK.

Now check if you can open the corrupt file. If not, try implementing the next method.

Method 3: Look For Automatically Recovered Excel File

If you have Excel’s AutoRecover feature enabled, you’ll have access to a copy of the Excel file corrupted or lost due to application crash, power outage, or accidental deletion.

The ‘AutoRecover’ feature saves Excel worksheets at a temporary location after a certain time interval. It saves the worksheets automatically and is turned on by default to reduce the chance of data loss.

Check if you can recover corrupted Excel file by following these steps:

Step 1: In Excel, open a Blank workbook.

Step 2: Go to File and click Options.

Figure 5 – Excel Options

Step 3: In the Excel Options dialog box, click Save, and then copy the ‘AutoRecover file location’.

Excel Options Window

Step 4: Open File Explorer window and paste the copied AutoRecover file location, and press Enter.

Step 5: A list of saved Excel files will be displayed. Choose the file you want to recover.

TIP: Use Excel’s AutoBackup feature to reduce chances of data loss, by saving a previous version of your spreadsheet automatically.

Use an Excel File Repair Software

If the above manual methods fail, repair the corrupt Excel file by using a third-party software, such as Stellar Repair for Excel**.** The software helps repair Excel (XLS and XLSX) files easily and effectively.

Read this: How to repair corrupt Excel file using Stellar Repair for Excel?

Some key features of Excel Repair software are as follows:

• Fixes all errors in the MS Excel file.
• Repairs multiple damaged Excel files in a go.
• Recovers chart, chart sheet, table, cell comment, image, formula, and sort & filter.
• Preserves properties and cell formatting of Excel worksheets.
• Previews recoverable Excel file data before saving.
• Recovers all data components from the corrupt files and saves them in a new blank Excel file.
• Compatible with Excel 2019, 2016, 2013, 2010, 2007, and lower versions.

Conclusion

You can try the workarounds discussed in the blog to open a corrupt Excel file without a backup. Disabling the protected view feature can help you open the file. If the issue persists then try repairing the corrupted Excel file using the Open and Repair utility. Although, it may not be able to fix a severely corrupted workbook. In such a case you can use Stellar Repair for Excel . It is an advanced tool that can help you repair a corrupted Excel file with 100% integrity.

[Fixed] Excel PivotTable Overlap Error | Troubleshooting Guide

In Excel, you need to refresh the pivot table data source after adding new data. However, sometimes, while refreshing the pivot table, you may experience an error “PivotTable Report cannot Overlap.” This issue usually appears when there are multiple pivot tables in a single worksheet. It often occurs when you try to place one pivot table on top of another or if you try to set a common cell range to multiple pivot tables. However, there are many other causes associated with the error.

Reasons for a pivot table report cannot overlap another pivot table report issue:

• Merged cells in a pivot table may cause the overlap issue
• Using the same range of cells for multiple pivot tables
• Hidden columns
• Preserve formatting option is enabled
• Modifying the pivot table using a macro that is corrupted
• Using the workbook.RefreshAll method incorrectly
• Number of pivot items goes beyond the number of cells available
• Excel file is corrupt
• Corrupted Pivot table
• Some columns are labeled with the same name

Methods to Fix Excel PivotTable Report Cannot Overlap Error

You can get the pivot table overlapping issue if the field in pivot table crossed the maximum items limit. According to the Microsoft guide, you can specify up to 1,048,576 items to return per field. Check the cell fields in your pivot table. Also, make sure each column’s label is unique. Sometimes, the hidden columns or hidden sheets can also prevent you from modifying the pivot tables. You can check for hidden columns in the Data view.

If the error still persists, then try the below-mentioned methods to fix the error.

1. Move the Pivot Table to a New Worksheet

The “PivotTable Report cannot Overlap” error can occur if there is an issue with the columns in the pivot table. In this case, you can try moving the pivot table to a new worksheet. Moving the pivot table to a different worksheet automatically resets the column width according to the new sheet and creates space that can help in preventing the overlapping issue. Here are the steps to do so:

2. Disable the Background Refresh Option

When the background refresh option is enabled, then Excel updates the pivot table in the background after every minor change. It may create issue if you have a large-sized Excel file with multiple pivot tables. You can try disabling the background refresh option. Here’s how:

• The Connection Properties dialog box is displayed. Unselect the “Enable background refresh” option and select the “Refresh data when opening the file”
• Click **OK.

![enable background refresh in connection properties window](https://www.stellarinfo.com/public/image/catalog//article/Repair-Office-Documents/Recover-Excel-Files/pivottable/enable-background-refresh-in-connection-properties-window.jpg)

**

3. Disable Autofit Column Widths

When the Autofit column widths option is enabled, Excel automatically resizes the pivot table whenever you make changes to it. These automatic adjustments can sometimes add or remove fields which can result in the PivotTable Report cannot Overlap issue. To fix this, you can disable the “Autofit column widths on update” option. To do this, follow these steps:

• Right-click on any field on the pivot table.
• Select **PivotTable Options.

![Select Pivot Table](https://www.stellarinfo.com/public/image/catalog//article/Repair-Office-Documents/Recover-Excel-Files/pivottable/select-pivot-table.jpg)

**

• In the PivotTable Options window, unselect Autofit column widths on update.

  

• Click on the OK.

4. Check the Workbook.RefreshAll Method

Several users have reported experiencing the “Excel PivotTable Report cannot Overlap” error when using the Workbook.RefreshAll method. This method is used to refresh data ranges in the pivot report. Sometimes, the error can occur due to missing variable that is representing an object (workbook) in a query. So, make sure you’re using the Workbook.RefreshAll function correctly.

5. Repair your Excel File

You may also encounter the “A PivotTable Report cannot Overlap” error if the Excel file is corrupted. You can use the inbuilt utility in Excel - Open and Repair to repair the corrupt file. Here’s how:

• In your Excel application, click on the File tab and then click Open.
• Click Browse to select the desired file.
• In the Open dialog box, click on the corrupted file.
• Click on the arrow next to the Open button and then click Open and Repair.
• Click on the Repair
• In the displayed message, click Close.

If the “Open and Repair” utility fails to fix the issue, then it means there is high level of corruption in the Excel file. To tackle this, you can take the help of a professional Excel file repair tool, such as Stellar Repair for Excel. The tool can easily repair severely corrupted Excel file and recover all the objects of the file, such as pivot tables, macros, charts, etc. with 100% integrity. You can download the free trial version of the tool to check its functionality.

Conclusion

In this article, we have discussed the possible reasons behind the “PivotTable Report cannot overlap” error in Excel. You can follow the methods mentioned above to fix the issue. The error may also occur if the Excel file gets corrupted. In this case, you can try repairing the corrupted Excel file using the Open and Repair utility or consider using Stellar Repair for Excel . The tool makes the process of repairing the Excel file smooth and quick.

Best Excel Repair Software till Date - Try Now

Summary: In this blog, we overview and conclude Stellar Repair for Excel as Best Excel Repair software till date – based on its distinctive features and capabilities. Also, you’ll get to know what makes it the top Excel repair software from the perspective of recognized review websites, tech community forums, and users. In addition, you’ll find the simple and step-wise process of repairing Excel by using the software.

Corruption in Excel files can hamper workflow, bringing productivity to a halt. And what can be more concerning is that you may lose sensitive data if the corrupt or damaged file is not repaired on time. An Excel file may get corrupted due to various reasons.

Common Reasons Behind Excel File Corruption

• Abrupt system shutdown
• Human errors such as accidental deletion, formatting, or overwriting an Excel workbook
• Damaged Excel installation
• Hardware failure
• Virus infection or malware attack
• Bad sectors on the hard drive on which Excel files reside
• Large-sized Excel file

Regardless of the reason, manually troubleshooting corruption errors in an Excel file can drain time, resources and may even cause data loss. However, using a third-party professional tool such as Stellar Repair for Excel can save you the manual efforts and time in repairing Excel files, keeping the original data intact.

What Makes Stellar Repair for Excel the Best Software?

While there is no dearth of Excel file repair tools, Stellar Repair for Excel software has garnered considerable interest and positive reviews by MVPs . The software has remarkable features that make it the Excel file repair specialist.

Key Features of Stellar Repair for Excel Software

Though the software encompasses several great features and a simple-to-use and intuitive user interface, some of the key features that make it the best Excel repair software are:

• Restores Excel (XLS / XLSX) File in Original, Intact State

The software repairs corrupt Excel files and restores all the data in the original format. Also, it helps restore the original properties of cell formatting of the workbook.

• Capability to Resolve all Excel Related Errors

Most errors that crop up unexpectedly while working with Excel files are the result of damages caused due to human errors, virus infection, power surges, etc. The software can help you easily fix corrupted Excel files to get rid of errors such as “Excel is not responding ”, “Excel found unreadable content in name.xls ”, “Excel cannot open the file filename.xlsx”, etc.

• Real-Time Pre-Recovery Preview

It provides users with the opportunity to preview recoverable Excel file items before saving them. This helps users estimate how much data they will be able to salvage by using the tool, thus helping them make an informed decision about investing in the software.

Besides these features, some other aspects that make the software a recommended choice for Excel repair are as follows:

• 100% Secure****: Downloading and installing this software is 100% safe and secure, since Norton antivirus security comes installed with it.
• Tested by MVPs****: Stellar Repair for Excel software is tried and tested by credible MVPs.
• Allows Testing before Purchase: The software’s demo version lets you understand the tool and its advantages before buying it.
• Stellar is Microsoft Gold Partner****: The software’s vendor, Stellar Data Recovery, is a certified Gold partner for Microsoft.

Stellar Repair for Excel – The Most Recommended Software

Check out the user ratings and reviews to understand why Stellar Repair for Excel ranks as the top Excel file repair software, and why you should choose it over its competitors:

• Capterra – 4/5

A user has shared how effectively the Stellar Repair for Excel software repaired and restored the corrupted Excel file.

• g2.com – 4.5/5

The Excel Repair software got a rating of 4.5/5 on g2.com based on the positive reviews of the users.

• Softpedia – 3.5/5

Softpedia gave the product a rating of 3.5/5 and reported it as 100% clean (meaning without malware).

Support and Compatibility
Stellar Repair for Excel software supports the latest MS Excel versions 2019, 2016, 2013, and lower versions. It can operate smoothly on Windows 11, 10, 8.1, 8, 7, and earlier operating systems.
System Requirements
Stellar Repair for Excel requires a minimum Pentium Class Processor with 2 GB minimum memory and 250 MB of free storage drive space.

How to Use Stellar Repair for Excel Software to Repair Excel Files?

Follow these steps for repairing damaged or corrupt Excel files:

• Run the software and from the main software screen, select the corrupt Excel files you want to repair by clicking Browse or Search.

• Once the file is selected, click Repair to begin repairing the corrupt file.

• When the scanning finishes, all recoverable data is displayed in the left-pane of the preview window. Click on any item to preview its content in the right-pane.

• For saving the file, click the Save File button on the Home menu.
• When prompted, select a target location to save the repaired file and click OK.

The repaired Excel file will now get saved in the selected target location.

Concluding Lines

Stellar Repair for Excel  software empowers users to repair Excel (.XLS/.XLSX) files and restore worksheet data in the event of file corruption and data loss. More importantly, the software performs granular-level recovery to restore the complete file items while preserving worksheet properties and visual representation.

File Format and Extension of [filename] don’t Match in Excel File

Summary: The “File format and extension of [filename] don’t match. The file could be corrupted or unsafe” error message indicates that the Excel file you’re trying to open is unsupported, unsafe, or corrupted. Read this article to learn more about this error and how to fix this error. It also mentions an advanced Excel recovery tool to repair the corrupted Excel file and retrieve all its data in a few clicks.

You can encounter the “File format and extension of [filename] don’t match. The file could be corrupted or unsafe” error when the Excel application detects any issue with the file. This happens when you try to open an old version file format in a newer version or if the file is received from an unsafe destination. This can prevent you from opening the Excel file.

As indicated from the error message, this error occurs due to the following reasons:

• The file has incorrect file extension.
• The file is corrupted.
• The file you are trying to open is protected.

Now, let’s see how to resolve this Excel error.

Methods to Fix the “File format and extension of [filename] don’t match” Error

Try the following methods to troubleshoot the “File format and extension don’t match” error in Excel.

Method 1: Rename the Excel File

You can face the “File format and extension don’t match” issue if the file has incorrect extension. It can occur if the file extension has been altered or you’ve mistakenly saved the file with incorrect extension. To fix this, you can try renaming the Excel file with the correct file extension.  

Method 2: Check the Default Excel File Format

Different versions of Microsoft Excel use different default file formats. For example, .xls is the default file format of older versions (2003 and lower) of Excel, whereas .xlsx format is used by the newer versions (2007 and later). Opening the Excel file with an incompatible extension can cause the “File format and extension don’t match” issue. You can check the Excel version you are using and ensure it’s compatible with the Excel file you are trying to open.

Method 3: Change the Protected View Settings

You may receive the “File format and extension of excel don’t match” error if the Excel file is protected. You can check and try disabling the Protected View settings .  

Caution: Changing the Protected View settings can put your system at risk. If the Excel file is being downloaded from the internet, it may contain viruses that can infect your system. So be careful before disabling the Protected View settings.

Steps to Change Protected View Settings in Excel:

• In the Excel’s File menu, click on Options.
• Select Trust Center > Trust Center Settings.

• Under Trust Center, select Protected View and disable the below three options:
• Enable Protected View for files originating from the internet.
• Enable Protected View for files located in potentially unsafe locations.
• Enable Protected View for Outlook attachments.

• Click OK. Then, try to open the Excel file.

Method 4: Check and Provide the Excel File Permissions

Sometimes, you can get the error if you don’t have sufficient permissions to open the Excel file. This usually happens when you try to open the Excel file received from other sources. You can check and provide the desired permissions to fix the error. Here are the steps:

• Locate the affected Excel file, right-click on it, and select Properties.

• In the Properties window, click the Securities option and select Edit.

• In the Security window, under ‘Group or users name’, select the user names. Check the file permissions and make sure Full Control is enabled. If not, then click on the Add option.

• Click on the Advanced option in the Users, Computers, Service Accounts, or Groups window**.**

• Click the Find Now option. A list of all users and groups appears in the search field.

• Select “Everyone” from the list and then click OK.

• In the object names field, you will see ‘Everyone’. Click on OK.

• In the Permissions window, select “Everyone” and enable all options (Full Control, Modify, Read & Execute, Read, and Write) under Permissions for Everyone.

• Click Apply and then OK.

Method 4: Repair your Excel File

As the error message indicates, corruption is one of the causes of the “File format and extension of [filename] don’t match” error. If your file is corrupted, you can repair it using Microsoft’s built-in Open and Repair tool. Here are the steps to run the Open and Repair tool to repair corrupted Excel file:

• In Excel, click on File.
• Click Open and then click on Browse to select the corrupted Excel file.
• In the Open dialog box, click the Excel workbook (in which you are facing the error).
• Click the arrow next to the Open button and select Open and Repair.
• Then, click Repair to recover as much data as possible.
• The Excel prompts a message after the repair process is complete. Click Close.

The Open and Repair utility may fail to give the intended results. In such a case, you can repair the corrupted/damaged Excel file using a specialized Excel repair tool . Stellar Repair for Excel is one such tool that can repair severely corrupted Excel files. With the help of this tool, you can quickly recover all the objects from the Excel file. The tool has a simple user interface that even a non-technical can use to repair the Excel files. The tool can also repair multiple Excel files at once. You can check the tool’s functionality by downloading its demo version.

Closure

You can encounter the “File format and extension of [filename] don’t match” error due to different reasons. To resolve the issue, you can check the file extension, permissions, protected settings, etc. If you suspect the error has occurred due to corruption in the Excel file, you can try repairing the Excel file using the Open and Repair tool. If nothing works for you, then try Stellar Repair for Excel . It can repair highly damaged Excel files and recover all the data while preserving the file properties and cell formatting. The tool can help you fix all the common corruption-related errors quickly.

[Fixed] Excel Cannot Open the File Because the File Format or File Extension Is Not Valid

When opening an older version of an Excel file in a newer version, you may encounter the “Excel cannot open the file because the extension is not valid” error. This happens if you have accidentally renamed the file with a different file format or an incorrect file extension. Also, you may get the ‘Excel cannot open the file’ error if the file has become unreadable or corrupted.

This is how the complete Excel error message looks like:

“Excel cannot open the file filename.xlsx because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file.”

Check out this video for a quick demonstration of how to fix “Excel Cannot Open the File Because the File Format or File Extension Is Not Valid”

How to Fix the ‘Excel Cannot Open the File Because the File Format or Extension Is Not Valid’ Error?

Try any of these workarounds to fix the error and regain access to your Excel file data:

Workaround 1 – Change the Default File Format

By default, an Excel file is saved in .xlsx or .xls file format. Trying to open the file with a different or incorrect extension may cause the ‘Excel cannot open the file because the extension is not valid’ error. To fix the error, try changing the Excel default file format by following these steps:

Note: Take a backup of the Excel file that you cannot open and try the steps on the backup copy.

• In Excel 2010 and newer versions, click on the File menu.

Note: For Excel 2007 and earlier versions, click on the Office button.

• On the left panel, click on Options. 
• In ‘Excel Options’ window, under Save workbooks section, click on the Save files in this file format: drop-down. Select a file format (i.e., the one supported by your Excel version).

• Click OK.

Check if you can open your Excel file. If not, try the next workaround.

Workaround 2 – Edit the Excel File Permissions

You may receive the ‘Excel file format or file extension is not valid’ error if you lack sufficient permissions to open the file. Usually this happens when you try to open an Excel file received from some other user. Follow these steps to change the file permissions and see if it fixes the problem:

• Right-click on the file that won’t open and click Properties.
• In the file properties dialog box, click the Security tab and then hit the Edit button.

• When the file’s permissions dialog box appears, click on the Add button.

• Click on the Advanced button from the ‘Select Users or Groups’ window.

• Select Find Now. A list of all users and groups will get displayed in a search results box. Choose Everyone group from the list and hit OK.

• You can see the ‘Everyone’ group in the ‘Enter the object names to select’ textbox. Click OK once again to return to the file’s permission dialog box.

• Click Everyone from the Group or user names: box and check all the checkboxes under Allow.

• Click on Apply and then OK.

Now try to open the Excel file. If you’re still getting the Excel file cannot open error, use the following workaround.

Workaround 3 – Recover Unsaved Workbook

If the ‘Excel file extension not valid error’ occurs when attempting to open an unsaved workbook, do the following to recover the unsaved workbook:

• In Excel, click File. 
• From the Info screen, under Manage Versions, click Recover Unsaved Workbooks.

Excel will list any unsaved files. Try opening the file and save it. If this doesn’t work, skip to the next workaround.

Workaround 4 – Repair the Workbook

If none of the above workarounds has worked for you, chances are that the Excel file has become corrupted. Try to repair the file using the Excel inbuilt ‘Open and Repair’ utility by following these steps:

• In your Excel application, click on File > Open.
• In the ‘Open’ dialog box that pops-up, select the Excel file you want to repair and click the arrow next to the Open button.

• From the dropdown list, select Open and Repair.

• Excel will ask you to attempt to repair the file or extract data from it. Click Repair to retrieve maximum data. If the Repair option fails, click on Extract Data to recover the data without formulas and values.

If the ‘Open and Repair’ utility doesn’t help fix the corrupted file and/or recover the data, use an Excel repair tool  such as Stellar Repair for Excel to regain access to your file and its data.  

Stellar Repair for Excel software can help repair severely corrupted XLS and XLSX files. Also, it helps recover all the file components, including tables, pivot tables, cell comments, charts, chart sheets, images, formulas, etc., without impacting the original structure of the Excel file. 

To learn how the software works, read this: How to repair corrupt Excel file using Stellar Repair for Excel?

Conclusion

You may encounter the error ‘Excel cannot open the file because the extension is not valid’ when opening a workbook with a different file format or an incorrect file extension. Also, the error may occur if the Excel file has turned corrupt. This article has covered some of the most effective workarounds to resolve the error. But if nothing works, you can try to repair the Excel file and retrieve its data using the Stellar Repair for Excel software.