Error when deleting SharePoint Online folder or file

You may encounter an error while deleting a folder in SharePoint Online - You have to delete all the items in this folder before you can delete the folder.

This usually occurs when the folder has sub-folders or files within and the SharePoint site has the preservation 'On-Hold' policy enabled for DLP (data loss prevention). When the site is on hold, files can be deleted directly but folders cannot be deleted unless all sub items are deleted.

⛏️ SOLUTION

The error message hints a solution - delete all files/folders within the folder and then delete the main folder.
Here are few ways you can try, whichever is convenient.

1. Disable the on-hold for the site from Microsoft 365 Security and Compliance center (required Global Admin permissions). You can re-enable after deleting the folder.
2. Delete all the files and sub-folders manually.
3. Use PowerShell to write a script, loop through all sub items, and delete them.
4. Use "View in File Explorer" option to manually delete files, this will give you a desktop like feeling.
5. Ensure you have no checked out files in the folder.

You may come also come across a strange behavior, getting error 'You have to delete all the items in this folder before you can delete the folder' while deleting a SharePoint file.

This may happen when the library is corrupted (say due to a migration) and files are treated as folders.
Check if you have a default Content Type associated with the document library, if not, then add a default Content Type "Document" and set it for the problematic file from the document properties screen.

The same steps apply to OneDrive for Business, if you face same issue.