Excel cannot be open the file 'filename.xlsx' because the file format or file extension is not valid

Occasional Visitor

Hi All,


I have a excel.xlsx file saved in my system which has been corrupted .I atleast need to recover the data stores .It is a file of 124 KB and has around 35 worksheets in the workbook .I have tried all possible ways to recover and repair the file .i even tried to extract the data using 3rd party application like stellar,ease of use recover application of excel still i have no luck . The below error message im getting whenever i try to open the file.I even tried to open it through other applications like wordpress,google sheets and so on but nothing works .




Thanks and regards ,


7 Replies

Can you attach the file for me to figure how to solve this for you?

This error message is encountered in the following scenarios:

  • The file is not compatible with the Excel-version
  • The file has become corrupt or damaged

I copied and pasted the file to my desktop, right-click and changed '.xlsx' to '.xls'. Boom!! I got my file back.
Try to open your corrupt file in safe mode. Press Windows+R and write excel.exe /safe and click OK.   Good Luck


@Muthu69 Hi. If you have tried all possible methods to repair your Excel file but none of them work, then maybe your Excel file is not corrupted, but you just don’t have permission to open it on your system. If you don’t have permission to open the Excel file, it will display the error "Excel cannot open the file because the file format or file extension is not valid." I have tested this on my Windows 10.  You can use the following steps to grant everyone on this computer permission to open the Excel file. 

  1. Right-click the Excel file that cannot be opened and select Properties.
  2. After the file’s Properties dialog opens, select the Security tab, and then click the Edit button.
  3. After the file’s Permissions dialog opens, click the Add button.
  4. When the Select Users or Groups dialog opens, click the Advanced button. When the next dialog opens, click Find Now so all users and groups will show up in the search results list at the bottom of the dialog. Select the Everyone group from the list, and then click OK. Click OK again.
  5. When you return to the Permissions dialog, you will see the Everyone group has been added to the group or user list. Select the Everyone group, check all checkboxes under Allow, and then click Apply.

That’s it. Now check if you can open the Excel file without any problems. If you want an illustrated guide, refer to this page: https://www.isumsoft.com/office/excel-cannot-open-the-file-because-extension-is-not-valid.html#way2


Please tell me if this helps. Good luck!


"I copied and pasted the file to my desktop, right-click and changed '.xlsx' to '.xls'. Boom!"

What did you click on when you right clicked in order to change the file type from xlsx to xls? Because I just tried this and cant figure it out.
I just tried this and it didnt work. Its still telling me the file doesnt match. So basically my excel file wont open as an xlsx or an xls? Why not?!!! This is really annoying!!! I just got a new laptop and im trying to open my bills spreadsheet, but for the life of me cant get the file to open. This is ridiculous!! I just want to open the dang file. Why does everything have to be so fricken complicated!??!?!


With your permission and everyone involved, if I can recommend.

It can help us all if you upload an Excel file, no picture.

You could get a precise solution much faster with a file.

This would also be a blessing for all of us,

as we can understand the problem much better,

a win-win situation for everyone.


*Knowledge of Excel version and the operating system is a must have if you want to proposing a reasonable solution (Example: office version e.g. 2016 or 2019 or 365 web or 365 pro, etc) and your operating system (e.g. Win10 (2004), Win 10 (1903), Mac, etc.).


Thank you for your understanding and patience




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