a johnson2
Thank you for posting in the microsoft community
The $ symbol indicates a hidden file, which usually appears in the system or a cached file in an application.
If he is currently being called, then you may not be able to copy it directly to your USB.
Back to your question, we suggest you to exit Icloud and make sure there is no Icloud synchronization process in the process before backing up the data in Icloud folder to USB.
Before that, please make sure all Icloud files have been synchronized and uploaded to the cloud, and we also recommend you to backup your important personal data just in case.
I hope the above information can help you.
Sincere Wish
Shawn Z | Microsoft Community Support Specialist