Command: Unshare Workbook
Alt + R U 2 unshares a workbook in Excel. This removes the shared workbook feature, preventing multiple users from editing the workbook simultaneously. This is useful when you no longer need collaborative editing on a file.
This is how to do Alt + R U 2 on Mac in Excel with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with Excel.