A shared Excel file is missing and an error "the file format or file extension is not valid" appears

Sally9

I am the owner of a shared excel file that is now missing. I cannot see it listed, it is not in my deleted items. I went to my events, and see that the document was edited 2 weeks ago by a colleague. When I try to open it I get the message that " 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."

Advice?

Mark

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@Sally9 wrote:

When I try to open it I get the message that " 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."

Advice?

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That often means the extension has been changed or removed. 

Make sure the file is still called whatever.xls or whatever.xlsx depending upon your version of Office. 

 

It may also be possible to restore a previous version https://help.dropbox.com/delete-restore/version-history-overview