Can not open XLXS file on network drive - Error: Excel cannot open file 'file.xlsx' because file format or extension is not valid

Matt DeVerna
Matt DeVerna used Ask the Experts™
on
Hi,

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.
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Qlemo"Batchelor", Developer and EE Topic Advisor
Top Expert 2015

Commented:
For test, rename to *.zip, and then open in Explorer (since 2007 Office files are ZIP files).
ShumsManaging Director/Excel VBA Developer
Distinguished Expert 2018

Commented:
Hi Matt,

Try deleting the temp file in this folder: C:\Users\%username%\AppData\Roaming\Microsoft\Excel\XLSTART

Author

Commented:
Qlemo - Renaming to Zip did not work. It would not open at all

Shums - There are not any files in the path you specified
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ShumsManaging Director/Excel VBA Developer
Distinguished Expert 2018

Commented:
Search XLSTART in your explorer. Path differs from Windows operating system, which one do you use?

Author

Commented:
I copied to desktop and renamed using CMD prompt to XLS. It did not fix the same issue. Same problem

Author

Commented:
I have some desktops that are win 7, Win 10 and I am doing this on the server - 2016 essenials

Author

Commented:
There was 2 folders with XLSTART. Neither had anything in them
"Batchelor", Developer and EE Topic Advisor
Top Expert 2015
Commented:
If the file renamed to ZIP does not open, it is corrupted in a way probably no repair will be feasible. You can try if one of the common ZIP tools like 7zip is able to read and repair.

Author

Commented:
The file was corrupted. I even downloaded some tools to fix it and it still would not open

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