Windows 11 Update on 24/07 and now I can't open any excel files, these were all working previously

[CathieSwan]

Hi guys,

Hoping you can help me.

All the files were working completely fine yesterday, until after I ran the Windows update last night. Today, none of the files I need will open, I'm getting the same error message for everything.

"Excel cannot open the file 'XXXXX' .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"

I've tried multiple troubleshooting processes; permissions, previous version, DDE, all sorts. Nothing is working.

This is clearly linked to the update rather than the files themselves, does anyone know if the latest update has caused Excel files issues and if so, how do I fix?

[#2]

@CathieSwan 

Can you open such file from File->Open after the running Excel app?

[#3]

@SergeiBaklan that doesn’t work either sadly 

[#4]

@CathieSwan 

Strange. Even if you create new workbook, save it and try to open from another Excel?

If so I'd try to  Repair an Office application - Microsoft Support

[#5]

I solved my problem.  I was running Windows 10 and MS Office 2013.  After upgrading to Windows 11 my Excel shortcuts would not open target files.  After 3 days of unsuccessfully studying the internet blogs and trying out the handfull of solutions found therein, I finally solved my problem as follows: (1) rolled back to Windows 10, (2) uninstalled MS Office 2013, (3) re-installed Windows 11, (4) re-installed MS Office 2013... easy peasy all systems go.

@CathieSwan