can't open an excel file

This usually means one of these happened:

• The file extension does not match the actual file format.
• The workbook became corrupted.
• The file was renamed or saved incorrectly.

Try these steps in order:

1. Check whether the file is really an Excel workbook
   • Confirm the file still ends with .xlsx.
   • If the file was renamed accidentally, Excel can show the “file format or file extension is not valid” message.
2. Only open it if the file source is trusted
   • If the file came from an untrusted source, do not open it.
   • If it is a file created and used regularly, that trust check is already satisfied.
3. If the file was renamed or saved with the wrong extension, open it and save it again correctly
   • If Excel allows it to open after the warning, save it again using the correct Excel file format and extension.
4. If the workbook may be corrupted, try restoring an earlier version
   • Go to the folder where the file is stored.
   • Right-click the file.
   • Select Version history.
   • Choose an older version.
   • Select the three dots or dropdown next to that version.
   • Select Restore.
   • Warning: restoring replaces the current version, so changes made after that version will be lost.
5. If the file was opened from email, save it to the computer first
   • Then open it in Excel.
   • If needed, ask for it again in .xlsb or .xls format.

If this started immediately after editing the date in the same workbook, the strongest supported possibility is that the workbook became corrupted or the file contents no longer match the .xlsx extension.

• A file is in a different format than its extension indicates in Excel
• Restore a previous version of an Excel file