Corrupted Excel file?

Try restoring a previous version from OneDrive (right-click file → Version history). If that fails, use Excel’s Open and Repair (File → Open → select file → dropdown → Open and Repair). If neither works, you may need to recover from a backup.

There are several approaches you can try to recover it.

Try Excel’s built-in repair function

1. Open Excel (without opening the corrupted file directly).
2. Go to File → Open → Browse.
3. Select your file.
4. Click the small arrow next to Open and choose Open and Repair.
5. When prompted, try Repair first. If that doesn’t work, try Extract Data.

Check OneDrive version history

Since your file is saved on OneDrive:

1. Go to OneDrive in your browser.
2. Locate the file, right-click it, and select Version History.
3. You might find an earlier, intact version of your file that you can restore.

Look in AutoRecover / Temporary files

Office 365 often saves temporary copies:

• On Mac, check:

~/Library/Containers/com.microsoft.Excel/Data/Library/Preferences/AutoRecovery

• Look for files with similar names to your document. They might be recoverable.

Try opening it in another program

• Sometimes Google Sheets or Libre Office Calc can open files that Excel cannot.
• Upload the file to Google Drive and open it with Google Sheets—it might recover at least some of the data.

Use Excel Online

• Open Office 365 online (Excel Online) and try opening the file from OneDrive.
• Sometimes the online version can recover files that the desktop version cannot.

After recovering your file, save multiple copies or enable AutoSave in Office 365 for extra protection against crashes.

But I still hope this helps at least a little bit.