Hello.
Just to make you know you're not alone : I experience something similar.
I had my Sansa Clip Zip working fine with rockbox (latest release), but after many months of happiness, my player started to behave weirdly when i plugged it to my computer :
- if running the official firmware, I could browse my Clip, and it's sd card, copy, delete, whatever ;
- if off, or if running rockbox, my player froze, with a message I cannot remember of.
Following an advice, I have installed the latest build, but now I experience the same symptoms you describe :
- with official firmware on, everything is OK ;
- when off, or with rockbox on, I see two drives letters showing empty drives. No more freezes, which is a progress.
The problem drove me here today, and thank to you I know I'm not alone suffering this. Then may I say our players are not exactly dysfunctional : it's more like we have found an undocumented feature. :-)
I know I played a lot with the configuration, with the interface... Maybe I did something wrong. I'll make a fresh install, just to see...I'm confident in the developer's tremendous work. rockbox will prevail over this small annoyance.
I'll dig further and report my founds here.
Burrhus.