On Lion, when attaching a USB flash drive I would get the pop up asking which machine to mount it to, Mac or Win VM. Since upgrading to Mountain Lion I get the same pop up, but OS X already mounted the drive and it will cause an error if I choose Windows. Before the upgrade, OS X didn't mount it anywhere until I made a choice. As a workaround, I eject the drive in Finder, then mount the USB drive from the VM menu.
Same issue here as well Running: - Mountain Lion 10.8.2 - Parallels Build 7.0.15106 (Revision 786747; August 3, 2012) - Windows 7 running off Bootcamp partition
I have this exact issue also. As with nycmike, OS X mounts the USB flash drive before I've responded to the pop-up, resulting in the following message when you choose to use it in the guest OS: OS X ML 10.8.2 with supplemental update 1.0; Mac mini 2011; latest version of Parallels a/o this post; Windows XP SP3 guest OS.
I've created an official support request, referencing this thread. Hopefully a fix will be forthcoming promptly.
Any update? Having the same issue here. Feel like it happened once before many versions ago and it was fixed in an update. Anyone got anything on this one? Thanks, BK