— This may have multiple causes like large files, spending time on validation...

— Open the Excel application, go to Options > Advanced > General > Clear...

— In order to fix the issue, press Alt + Ctrl + Delete key combination and close...

— It seems like there may be an issue with the Excel file or how the program is...

— Unfortunately, there is no information whether you can run the command to open...

— Yes, you can export a multi-sheet Excel file to CSV using the built-in menu...