Update/Resolution: Found the cause of this. I had installed the doubletwist media player, and one of its options is to automount USB storage. This can be disabled from within the player. I'm having something odd happen - at first I thought it was related to trying out ADW, but now I'm not so sure of that. I've switched back to TouchWiz & I'm still seeing the problem after a reboot, though I thought switching back had made a difference on it earlier. When I connect my Vibrant via USB cable to a PC, it automatically mounts as mass storage rather than the previous default behavior of having to pull down and enable it (now I can pull down and disconnect it). This is annoying for a few reasons: I'd like to be able to just use a PC for charging without giving it access to the drives I don't really want to wait for the media scanner to run every time I disconnect it. It seemed to be exhibiting this behavior when plugged into a USB cigarette lighter adapter, which means I can't use anything in storage (like MP3s) if I plug it in while driving without fiddling around a bit. I've rooted and lag-fixed with RyanZA's OCLF, and I've also installed the Mobile AP and Captivate camera, so I'm way outside stock configuration. Any suggestions?