Microsft Excel can automatically save updates to spreadsheets. If Excel, or the system, crashes, when you reopen Excel you will see a Document Recovery pane on the left side of the Excel window with the message "Excel has recovered the following files. Save the ones you wish to keep."
Some of the documents listed may have been saved by the user without any subsequent changes being made and will have "Version created last time the user saved the file" beneath the file name as shown above.
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