Excel file format or file extension is not valid...

Question

An Excel file that I access daily and store in Onedrive will not open now and I receive the "Excel cannot open the file 'x' 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" prompt.   I have browsed these forums and not found a suitable solution.  I am the only one who accesses this file and I have tried to rename the file extension, open in safe mode, open and repair, change permissions, and autorecover, all to no avail.  Any help would be appreciated

Jeff

Answer 1

Dear JEFFJWOJCIN,
Thanks for participating in the Microsoft Community. I'm an Independent Advisor and I'll help you.

First, open Excel, Open file > Browse, find your file, select it, then in the open button, click in arrow, and click on Open and Repair.

If you not able to open it, maybe is due the file is corrupted, but if you have your files in a synced folder of OneDrive, you can restore a previous version in the version history, see this process below:

https://support.office.com/en-us/article/view-p...

Do not hesitate to ask if you need more information.
I hope it has been useful to you.
Regards,
Renzo.

Answer 2

Hi Renzo,

   The repair function yields the same prompt as before and is unsuccessful.   As far as trying to get to a previous version, I cannot access the file thru the app to even check for previous versions.  Through a browser I receive the " We're sorry, we couldn't open your workbook.  Its possibly corrupt or using a file format that's not supported." prompt.  

J

Answer 3

Do you have the same error in Excel Online?

Unfortunately, some times is not possible to repair Excel corrupted files.