I just inherited a new client and put in shadow copies and proper backups 9/8/17.
They have a XLXS document that was last modified on 8/23/17 and they are trying to access it today. However they get an error "Excel cannot open file 'file.xlsx' because file format or extension is not valid". This is happening on all the computers not just 1
I can not restore this file from backups because I just put them in and my shadow copies do not go back that far.
I have tried:
1. Renaming the file to xls - it does not work it just opens a blank excel doc
2. Repairing the document in excel- Does not work
3. Adding the network location to the trusted trust center
4. Copying it to a local C drive - Does not work, same error
5. Disabling hardware graphics acceleration
6. Making sure the xlsx is associated to excel in default programs
7. Checked Ignore other applications that use Dynamic Data (DDE)
I feel like I fixed this before with a reg key.
Can someone please help. This is a very important document for my client. If there is a software that will fix it I am open to purchasing.