There hasn't been a pattern that I discovered. This just happened now when I woke up (phone left charging overnight; Wi-Fi & Sync enabled) and I decided to come post here. Happened again yesterday afternoon when I got my phone out to play some music on the way home.
Every once in a while, I'd get lucky and the files would show up by themselves, but the only fool-proof way I've found to get the phone working properly again is a restart, which takes several minutes to do.
I am NOT running any task manager (well, I was but when this problem started up I checked another thread which recommended to remove the task manager, so I did).
Is anyone else experiencing this problem? Do you know of a fix, or is it just me?