There are special characters you cannot use in filenames because they serve other purposes within OneDrive and SharePoint. If you have a special character in your filename, OneDrive and SharePoint will not be able to sync. The best thing to do is rename/avoid using these special characters.
Don’t use the following characters in filenames on OneDrive or SharePoint:
" * : < > ? / \ |
If you have a file or folder with invalid characters, rename the file, and syncing your account should allow you to continue.
OneDrive and SharePoint Have File Path Limits
- The file path limit for OneDrive and SharePoint is 400 characters.
- The limit for a file or folder name is 255 characters.
- Try to exclude spaces from file and folder names. A space in a file path will be replaced by %20 in OneDrive, now three characters instead of a single space as you see it. Try using the underscore _ in place of a space.
If you are having issues with a OneDrive or SharePoint file, start by renaming the file in question. If you still need to free up space, start with a top-level parent folder to prevent issues in the future.