In a recent scenario we encountered some strange behavior with a few OneDrive's. In the middle of a migration some users reported strange behavior with the new Modern UI . While the migration all went smooth and the content was present in their account. It seemed impossible to access their OneDrive content through the UI.
When accessing their OneDrive it would show the nice ice-cream (or flat tire) error message. In this message stating that those Files where no longer accessible.
When clicking on the ‘Return to classic OneDrive’ it still failed. Clicking did reroute is to a 404 error, so this wasn’t working either.
However using the ‘old’ My Site URL like that we had (/personal/account/default.aspx) did show us a set of content. While I didn't notice it yet this page already held a clew to what went wrong…
After fiddling around with PowerShell to make sure the content was present (showing up any way we like except in the UI) we decided to post a bug. While walking through the behavior with the service engineer he pointed out that instead of showing the ‘Documents’ view in the page on the My Site it showed ‘OneDrive’. When digging into that we navigated to the OneDrive of the specific user through WebDav only to find that the user decided to rename the default Documents folder to OneDrive as he felt that this was more consistent.
So the next step is just to rename that folder back to ‘Documents’, and everything is fine again.
After that it is a matter of educating the users not to rename their Documents folder on their OneDrive (or to stop using WebDAV altogether..). Without WebDAV it is not possible to rename your folder and break the modern UI. So whenever you encounter a broken OneDrive that seems to have content but is not displaying it, make sure the Documents folder is not renamed..