PHDM 16, RECOVERY MEDIA BUILDER, issues (not totally paragon's fault)

Paragon PHDM 2016
BUILDING Recovery media, “USB DRIVE IN USE by another application”

Problem in BUILDING the recovery media. I insert a 32g USB-3 stick. It gets a drive letter, with files on it (I used it for a PRIOR recovery build, and it worked, in PHDM 15)
I select RECOVERY MEDIA BUILDER, and it starts to progress, then says “OPERATION FAILED to write to USB, it is in use by another program”.
Now, I know that that is not totally a PARAGON issue, but is there a WAY for PARAGON to tell me WHAT process is interfering?
SO, I then went to paragon to FORMAT that USB stick. SAME problem, can’t format unless I RESTART the compter system (because something else is interfering with that USB drive).
I try turning off any other routines that may be interfering, etc.
ALL I WANT TO DO is clean off this USB to let me make recovery media, WHILE IN WINDOWS.
So, I then went to Windows DISK MANAGEMENT, and unassigned the drive letter.
THAT actually seemed to work, it let me create the RECOVERY MEDIA.
BUT, if anyone knows an easier and more reliable way to allow the inserted USB stick, to be USED by PARAGON, replies are appreciated.