Library Manager error

I’ve been trying to move the files for all my Virtual Instruments onto another drive, and I keep getting the following error.

“HALion Sonic Factory Content cannot be moved. Make sure that the files are accessible and that all processes that may use this library are closed”

I suspect this might secretly be an Apple OS problem, but I’m wondering if anyone else has had this.

I’m running a “trash can” style mac OS 10.15.5 Catalina