Excel 2007 cannot open the file

Question

I keep receiving the following: Excel cannot open the file (name) 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 had trouble yesterday and was told that I had to "take ownership" of the file, which I did. Now I am getting this. Any suggestions?

Answer 1

Try this fix, edit your Registry.

Go to HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Excel\Security and create these dwords if they are not already there, assigning the values listed:

"AccessVBOM"=dword:00000001
"ExtensionHardening"=dword:00000000

Answer 2

The file might be corrupted. One way to check is to try and open it using an alternative app. The Open Source app called LibreOffice can open Excel files and, like its counterpart, Openoffice, has been known to be more tolerant of broken Excel/Word files than the equivalent Microsoft products.