Here are a few steps you can try:
Check the Recycle Bin or Trash folder on your computer to see if the Excel file was accidentally deleted. If it is there, restore it.
If you recently saved the Excel file, try using the "Undo" feature in Excel to revert any recent changes that may have caused the data loss. You can also try the "Redo" feature to see if the data reappears.
Search your computer for the Excel file. You can use the Windows Search function or Spotlight search on a Mac. Make sure to search for both the file name and any relevant keywords.
Check if Excel has automatically saved a backup copy of the file. In Excel, go to the "File" tab, then select "Options," and click on "Save". Under the "Save workbooks" section, check if the "AutoRecover file location" is enabled and navigate to that folder to see if there is a backup copy of the file.
If none of the above steps work, you may need to use file recovery software to recover the Excel file. There are many file recovery software programs available, some of which are free. These programs can scan your computer's hard drive for deleted or lost files and attempt to recover them.