Excel users on different technical forums have reported encountering the error “Excel Cannot Open the File Because the File Format or File Extension Is Not Valid,” when opening the Excel file. Though it looks the error occurs due to incorrect file format or extension, there are various other reasons that can cause this error in Excel. In this article, we will discuss the possible reasons why the above error message occurs and look into ways to fix this error.
Reasons for the Excel Extension is not Valid Error Message
There could be any reason (listed below) why users encounter the Excel file extension not valid error message. When this error occurs, you are no longer able to open the affected files.
- Corruption in Excel file
- Incorrect file extension
- Excel file created with legacy Excel versions like 2000, etc.
- Insufficient file permissions
- Conflicting third-party add-ins
Proven Methods to Resolve the Excel Extension is not Valid Error
Discussed below are 4 effective solutions to resolve the ‘Excel cannot open file because the file format or extension is not valid’ error.
Method 1: Change the Default File Extension
As mentioned in the list of reasons above, incorrect or incompatible file extension can generate this error message. For example, if you try to open an .xls file in the new version of MS Excel (2007-2019) or vice-versa, you may instead see the Excel file extension is not valid error. There is a simple fix to eliminate it – change the file extension of the problematic Excel file. Here is how to do this:
Note: Create a copy of the problematic file before following the steps below.
- Start by launching MS Excel on your system.
- Select the file you want to open.
- Then, proceed further by clicking on File > Export.
- Click on Change File Type. Choose either XLS or XLSX, based on the version of your MS Excel.
- Click on Save As.
There is also an alternative way to change its extension. The steps are:
Note: Create a copy of the problematic file before using the workaround below, as changing the file extension may cause some issues.
- Go to the folder where the file is saved.
- Click on the View tab in the ribbon.
- Select the File name extensions option to make the file extensions visible.
- Then, select the problematic Excel file and right-click on it to rename it.
- Change the extension of the file proceeding the file name (.xls/.xlsx). Press Enter.
- It will show a prompt. Press Yes.
Try to open the Excel file again.
Method 2: Edit File Permissions
Sometimes, trying to open an Excel file downloaded from an external source may generate the Excel file extension is not valid error message. This usually happens when you don’t have sufficient permissions to read/modify it. You can change the permission settings and try reopening it. Here is how you can grant yourselves the permission to open it:
- Select the Excel file. Right-click on it and select Properties.
- Click on Security > Edit.
- In the Permissions dialog box, click Add > Advanced > Find Now.
- Choose Everyone from the list and click OK.
- Enable all checkboxes under Allow, click Apply, and OK.
Now, try to reopen the file.
Method 3: Restore Previous Versions
Seldom will you find yourself in a situation where you have lost all your progress made in an Excel file because of a sudden power cut or a system crash. Using the AutoRecover option (if enabled), you can restore lost data. This native feature automatically saves a copy of the file after regular intervals of time. These AutoRecover documents come in handy and can be used to restore the last version of the file.
So, if the AutoRecover is enabled in advance, utilize it to recover any unsaved workbooks. Here is how to do this:
- Launch MS Excel.
- Click on File > Info.
- Click on Manage Version and then Recover Unsaved Workbook.
- It will display a list of versions. Choose the most recent one (check the date/time stamp) to recover.
Method 4: Repair the Excel File
In some scenarios, you may get the Excel file extension is not valid error if the Excel workbook, which you are trying to open is corrupted. You can try repairing the corrupt Excel file using Open and Repair. It is MS Excel’s built-in feature that easily repairs corrupted or damaged Excel files.
If using the Open and Repair utility didn’t fix the problematic Excel file then the Excel file could be severely corrupted. In such a case, it is recommended to use a specialized Excel repair tool like Stellar Repair for Excel. It is an advanced and a reliable Excel file repair tool that is available as both a web-based application and a dedicated desktop application.
You can easily run via the online tool any web browser, and on any system, irrespective of the OS on it. It swiftly repairs a corrupted Excel file in three simple steps – Upload > Repair > Download. Its ease of use makes it ideal for users looking for a one-time solution to repair an Excel file.
If the issue is with a few Excel file, you can easily use the online Excel repair tool. But if it is widespread and has affected all your Excel files, you might want something more effective. In such a scenario, you can use the Stellar Repair for Excel desktop application.
It can repair XLS, XLSX, XLTM, XLTX, and XLSM format files without any hiccups. Moreover, it can retrieve formulas, references, cells, macros, etc., from a severely corrupted Excel file and restore them into a new workbook with 100% precision. The best part about this software – it works without the internet.
The desktop software can work on systems running on Windows 11, 10, 8.1, and 8, and supports Excel files created with Office 365, Excel 2021, 2019, 2016, and earlier versions.
Conclusion
If you are getting the Excel file extension is not valid error while opening an Excel file, you can try the various workarounds explained above. They should help you get rid of the issue at hand. If nothing helps you fix it and you are still getting the error, use a dedicated Excel file repair tool like Stellar Repair for Excel. It is a convenient way to repair corrupt Excel file/s or recover information from them.
