When our end-users who have read-only access synchronize a SharePoint document library, it seems to download the files from the cloud to their PC and sync without issue. The icon overlays all appear as green locks, as they should.

But on certain files the end-user is having issues opening. They receive the following error message: "Sorry we couldn't open filepath/filename"

We contacted Microsoft support for this issue, and the OneDrive senior internal support team recreated this same situation on their tenant.

In the end, the Microsoft support team said this was normal behavior for read-only users as a security measure. We were told that the minimum requirement to use the OneDrive sync client is edit permissions. They gave no resolution; only a work around which we feel is not feasible - Right Click on OneDrive in the system tray > Settings > Office tab > Uncheck the box: “Use Office 2016 to sync the files that I open.”

Right now, the best solution for us is to advise the read-only users to view all read-only files in the Online version of Office. (End-users with read-only permissions are able to view all files in online Office without any issues at all.)

Thank you for all of your help in advance.