Hi SamMam,
Based on your description, we understand that some users cannot open the files in the desktop app from SharePoint Online and when they open the file from their outlook, they cannot save the files to SharePoint.
Will these users have the following pop-up window when they choose the desktop to open the file? You can try a different browser to see if this problem can be solved.‘
If the problem persists,please check if there are any updates of Office. You can update your Office applications in the following ways: Open Excel -> File -> Account ->Update Options ->Update Now.
If your Office has been updated to the latest version, you can also try the following methods:
Go to Control Panel -> Programs -> right-click on Office applications’ icon -> Change -> Online Repair.
- Opening Office apps in safe mode to check whether there is an add-in or extension that may be causing a problem on startup.
- Performing a clean boot in Windows determine whether a background program is interfering with your Office application.
If none of the above methods can solve your problem, please provide the following information so that we can give further suggestions:
- Does the issue happen to all browsers?
- Screenshot of Office version (Open Excel > File > Account > Product information)
- Screenshot of the problem you are experiencing. Do you have any error message when app shuts down? If so, please share the screenshot with us.
- Does the issue happen to all Office files like Word documents, PowerPoint presentation, Excel workbook? Or only a specific type of file?
- Refer to Office URI Schemes, try to use URI link to see the result. For example: ms-excel:ofe|u|https://contoso.sharepoint.com/libraryname/filename.xls
Hope this will help you.
Tin