A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
If the worksheet tabs are missing but the file itself still opens, first check if the sheets were accidentally hidden. Right-click any visible sheet tab and select Unhide to see if the missing sheets are listed. If they're not there, check File > Info > Version History if the file is saved in OneDrive or SharePoint. You may be able to restore an earlier version where the tabs were still present.
Avoid making more changes to the file until you check the version history, especially if the missing tabs contain important data.