Xlsx File Format Not Valid

Xlsx File Format Not Valid. I've tried repairing on opening but i get the same message. Verify that file has not been corrupted and that the file extension matches the format of the file i have already tried all suggested solutions on microsoft forums like:

excel cannot open the file because the file format or file
excel cannot open the file because the file format or file from answers.microsoft.com

I've tried to change the file format to. But xlsx should be zip with some xmls inside, so the message differs: Excel cannot open the file 'filename.xlsx' because the file format or extension is not valid.

excel cannot open the file because the file format or file

File was saved as a strict open xml spreadsheet (*.xlsx) on a windows machine. Verify that file has not been corrupted and that the file extension matches the format of the file i have already tried all suggested solutions on microsoft forums like: Select excel in your default. Open your “previous version” tab for listing out the entire previously saved excel file version.