I agree with user, that has written following answer:
1 - I Started Parallels Desktop but I haven't started any VM. Only Parallels Desktop is running.
After that I connected my External USB Disk to my Mac but nothing happened. No disk visible on Desktop and no Disk appear on /Volumes/ folder.
Report ID: 86521795
2 - So I stopped Parallels Desktop, disconnected my External USB Disk e reconnected to my Mac. Now the USB disk appear on Desktop (and obviously on /Volumes/ folder)...
I started again Parallels Desktop and the USB icon stay on desktop...I can access to it.
Report ID: 86522243
3 - At the end I started Windows 7 VM and attached the USB disk to VM (the disk is just connected to my Mac before to start Parallels).... I can work on it from VM. After I disconnect my USB disk from Windows 7 and reattach to my Mac (but the USB icon doesn't appear on desktop and no appear on /Volumes/)
I can't access to my disk...!!! I have to stop Windows 7 Virtual Machine, Exit from Parallels, Disconnect my USB disk e RECONNECT it to my MAC...!!!
Report ID: 86522681
Thank You, is important for me using external USB disk with some different Vm and reconnect temporarly to my Mac and
website Mikonomi.dk... Tha worst is when Parallels is started, no VM started but connecting my USB DISK nothing happen...!
Thanks for your help!