We have mentioned the importance of automatically Syncing Your OneDrive Account.
However invalid characters within filenames and folders disrupt syncing.
The following special characters should not be used in file or folder names because they serve other purposes within OneDrive and SharePoint:
” * : < > ? / |
If you have a file or folder that contains any of these characters, rename it, and syncing should continue.
Learn more about the best storage for your needs in our Understanding the Difference between OneDrive, SharePoint, and Teams, article.