When Microsoft Excel detects a corrupted workbook upon opening, it automatically starts File Recovery mode and attempts to repair the workbook. If File Recovery mode doesn’t start, try using this manual process to recover your workbook:
Click File > Open.
Click the location and folder that contains the corrupted workbook.
In the Open dialog box, select the corrupted workbook.
Click the arrow next to the Open button, and then click Open and Repair.
To recover as much of the workbook data as possible, pick Repair.
If Repair isn’t able to recover your data, pick Extract Data to extract values and formulas from the workbook.
If neither the automatic nor manual method works, you can try some other methods to fix the file mentioned below:
https://www.stellarinfo.com/blog/simple-way-to-open-corrupt-excel-file-without-any-backup/
