Users unable to save changes to shared sheet due to sheet no longer shared.
Cause:
One of the users with access to the shared worksheet has turned off 'Allow Multi-User Editing'. This action automatically saves the file and immediately disconnects other users from the file. Even if the 'Allow Multi-User Editing' feature is turned on again, other users must first exit the file and re-open it before any changes can be saved.
Solution:
Save the open file under a different name and enable 'Allow Multi-User Editing'. Update the changes manually.
1) Save the open file under a different name.
a) Select the 'File' menu and select 'Save As...'
b) Type a different filename.
c) Click 'OK'.
2) Select the 'File' menu and select 'Close...'.
3) Open the file to be shared again.
4) Select the 'File' menu and select 'Shared Lists...'.
5) Click 'Editing' tab.
6) Select the 'Allow Multi-User Editing' check box.
Allow Multi-User Editing
7) Click 'OK'.
