The Excel file will get saved to your PC with a .xlsx extension, which can be opened in any spreadsheet app, including Microsoft Excel, Apple Numbers, OpenOffice, LibreOffice, and more.

To begin with, Microsoft Excel has one built-in AutoRecover feature using which you can repair the file and recover what was lost. There are two other viable ways by which you can retrieve the files.

To fix the Unknown error trying to lock file in Teams, Excel, OneDrive, PowerPoint, SharePoint, etc, Office apps use these proven solutions.