How do you fix Excel Cannot open the file XLSX because the file format or file extension is not valid?

There is always a number associated with such errors, to find that number press “Ctrl+Shift+I” and you’ll find “101590” at the lower-right corner of this message. There could be the following reasons behind this error;

  • The Excel file is corrupt or
  • The Excel file is not compatible with the version of MS Excel you’re using.

There are various Excel errors and ways to fix them, and this error can also be fixed easily. In this article, we have mentioned some of the useful methods to solve this error.

  1. Change the Extension of The Worksheet
    Many times, this error occurs due to the unsupported file extension of your file. So, make sure that MS Excel in your system supports the .xlsx extension. To check the support of .xlsx extension; 
    • open MS Excel and go to “File.”
    • Now, select “Export” and choose “Change File Type.”
  2. How do you fix Excel Cannot open the file XLSX because the file format or file extension is not valid?

    • Check whether it is showing the option of .xlsx or not. If not, then change the extension of the file. To change the extension, go to my computer and browse “Tools.” Now, choose the “View” tab and enable “File Name Extension.”
    • How do you fix Excel Cannot open the file XLSX because the file format or file extension is not valid?

    • After enabling the “File Name Extension,” you can change the extension of any file.
  3. Using “Open and Repair” Feature of MS Excel
    The “Open and Repair” feature of Excel allows you to repair the corrupted excel files. To repair a .xlsx file with this feature;
    • Open MS Excel and Go to “File” Menu.
    • Now, select the “Open” tab and click on “Browse.”
    • Choose the file which you want to open, but instead of opening the file directly, choose “Open and Repair” option from the below right side of the opened window:
  4. How do you fix Excel Cannot open the file XLSX because the file format or file extension is not valid?

From this feature, you can easily repair and open the corrupted .xlsx files.

  1. Excel Repair Software
    If none of the above methods helps in solving the problem, then try using Kernel Excel Repair software. This tool can help you repair corrupt excel files and make your worksheet accessible immediately. This utility offers some great features to solve your query, such as;
    • Repairing of both .xls and .xlsx file formats.
    • No file size limitation.
    • Compatibility with all versions of Excel – including MS Excel 2016.
    • Preview of recovered files before saving.
    • Quick and easy to use.

    For better understanding, let’s have a look at the working process of this tool.

Using Kernel Excel Repair is very simple. The user-interface of this tool is specially designed keeping the usability of users in mind. Follow these steps to use the tool:

  1. Download Excel recovery and launch it on your system
  2.  

    How do you fix Excel Cannot open the file XLSX because the file format or file extension is not valid?

  3. A window will appear on the screen, now “Browse” the Excel file which you want to repair with this tool and click “Repair” like this:
  4. How do you fix Excel Cannot open the file XLSX because the file format or file extension is not valid?

  5. The repairing process will take a few seconds (depending on the file size). Once the file is repaired, you’ll be able to see all its content, like this:
  6. How do you fix Excel Cannot open the file XLSX because the file format or file extension is not valid?

  7. You can save the file at the desired location on the computer. Just click the “Save” button and select the location where you want to save it.
  8. How do you fix Excel Cannot open the file XLSX because the file format or file extension is not valid?

This way you can easily access the data of your corrupted .xlsx file.

Final Words

“Excel cannot open the file ‘(filename)’.xlsx because the file format for file extension is not valid” is a common error that any user can face while opening a .xlsx file. With the help of the above methods, this error can easily be resolved without affecting the integrity of the file.

Priyanka is an entrepreneur & content marketing expert. She writes tech blogs and has expertise in MS Office, Excel, and other tech subjects. Her distinctive art of presenting tech information in the easy-to-understand language is very impressive. When not writing, she loves unplanned travels.

Despite the increasing challenges from competitors like Google Sheets, Microsoft Excel remains the most used spreadsheet app. It’s the app of choice in most workplace settings. What’s more, it includes numerous tools that help streamline and ease workflows.

Excel, like every other Microsoft app, occasionally runs into issues. Most of these are mere annoyances and can be solved with one or two program or system reboots. However, the “Excel cannot open the file because the file format or extension is not valid” issue has proved to be more bothersome for several users.

If you encounter this message when you try to open a file in Excel (or an Excel file), this guide will be helpful. We explain the possible reasons why the error can occur and three solutions that could work for you.

Excel Cannot Open the File Because the File Format or File Extension Is not Valid

When any user encounters this error in Excel, it’s usually due to one of two reasons:

  • The file is corrupted.
  • The file extension isn’t supported.

A corrupted file is unlikely to be opened by the parent program. Even if it successfully opens, it’s likely to have multiple errors such as missing data or unreadable portions. Excel and several other programs go the extra mile and simply don’t open corrupted files. It’s up to the user to try and fix the file corruption first or use another document with uncorrupted data.

Sometimes, the corruption is caused by malware that infiltrated the system. This can happen if your system isn’t fully protected when working with Spreadsheets on the web. Unrelated internet activity can cause this as well. After all, some malware types are known to be distributed as macros that can attach to Office documents.

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Sometimes, this error could be due to incompatible or unsupported file formats. Versions of Excel since 2007 use Office Open XML as the primary file format but are backward-compatible with the earlier versions of Excel files. A glance at the file extension will tell you straight away whether the program can open that file.

If the file you’re attempting to open is in one of these formats, it won’t open because it’s been corrupted. That’s because the file extension is compatible with Excel:

Excel Workbook. xlsx

Excel Macro-enabled Workbook. xlsm

Excel Binary Workbook. xlsb

Excel Macro-enabled Template. xltm

Excel Add-in. xlam

Spreadsheet. xls

Excel Template. xlt

Excel Macro. xlm

In addition, documents in these non-Excel file extensions can be opened by the program, though functionality might be reduced in some fashion:

XML. Spreadsheet 2003 or XML formatted files. xml

Lotus Spreadsheets. prn

Tab delimited/Unicode text files. txt

Comma-separated values files. csv

Data Interchange Format files. dif

Symbolic Link Format text files. slk

dBase Data Files. dbf

OpenOffice Files. ods

XML Paper Specification Files. xps

Portable Document Format files. pdf

Note that this isn’t an exhaustive list. Excel can open files with other extensions, including html.

How to Fix the “Excel Cannot Open the File Because the File Format or File Extension Is not Valid” Issue on Windows 10

Sometimes, when opening a file in Excel, the program displays this error message instead:

Microsoft Excel

Excel cannot open the file [File Name] 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.

If you encounter this error in any version of Excel since Excel 2007, three options are open to you:

  1. Check the file extension and change it if needed.
  2. Repair the file with Excel’s inbuilt repair tool.
  3. Change group permissions for the file.

Let’s explain each option in more detail.

Solution 1. Check the File Extension

If you’re unable to open the file, it could be due to an unsupported file extension. To be frank, this is very rare nowadays since most spreadsheets use a format Excel can open. However, if you’re trying to open the document on a pre-2007 Excel program, you can have issues with certain files.

There are two scenarios here:

  1. The Excel file is not opening in a legacy version of the program.
  2. The file is not opening in Excel because of an unsupported format.

In both instances, the solution is the same. Open any Excel file (or just launch the program and open a blank spreadsheet) and click the File tab. Next, click Open > Browse and locate the file you’re trying to open.

Now, look under the file name field and change the file extension. If you’re trying to open an xlsx document in a legacy Excel version, change the extension to xls. If you’re trying to open a document in an unsupported or less common file format, change the extension to xlsx or xls.

Save the change and then try opening the file again. If everything is done right, the file should open now.

Solution 2. Repair the File

When you get the “Excel cannot open the file because the file format or file extension is not valid” error, it’s likely because the spreadsheet is corrupt. If you manage to open the file anyway, there might be multiple errors and we’re sure you don’t want that. It is better to try repairing the file first and that is exactly what we’re going to do.

  1. Open a blank spreadsheet in Excel.
  2. Select the File tab and click Open.
  3. Hit the Browse button and choose the problematic file.
  4. In the file selection window, click the Open drop-down menu and select Open and Repair.

Excel will attempt to repair the file and then open it.

Solution 3. Change Group Permissions

In rare instances, the “Excel cannot open the file because the file format or file extension is not valid” error happened because the file has special permissions. Removing this permission will allow your Excel program to open it without issues.

How do I fix XLSX format is not valid?

How to Recover Excel File When the File Format or File Extension Is Not Valid.
Right-click the inaccessible Excel file and choose "Properties"..
Open the "Previous Version" tab to list all the previously stored versions of the Excel file..
Choose the most recent version and click "Restore" to retrieve the spreadsheet..

How do you fix this workbook couldn't be opened because the file format may not be matching with the file extension?

In Microsoft Excel, click File and then Options. Navigate to Save. At the "Save files in this format:" option, select "Excel Workbook (*xlsx)". This will resolve the issue for new spreadsheets saved via the add-in.

How do I open an Excel file that says an extension is not valid?

Fix Excel File Format/Extension Is Not Valid [5 Solutions].
Solution 1. Changing to Another File Extension..
Solution 2. Recover Unsaved Workbooks..
Solution 3. Restoring Previous Version of Excel File..
Solution 4. Using Open and Repair Feature..
Solution 5. Repair Corrupted Excel File..