I' sure it's a rockbox-problem (USB-Port).
Load for synching the original firmware (player off -> connnect to USB -> OF should load automatically) and it should work just fine.
After reboot of th player (disconnect usb) you can use rockbox again as usually.

I'm syncing using Rockbox. MediaMonkey sees it as a drive. One drive for the internal memory and one for the external memory. It seems strait forward.

Are you syncing with running rockbox or with running original firmware.
I'm using the original firmware when syncing and have no problems with my e280.

I'm not sure if all USB-Problems are solved in rockbox.

When I try to sync or copy songs to the Sansa, after about 10-20 songs the Sansa locks up and MediaMonday aborts. I have to disconnect and reconnect the Sansa. I've tried changing the folder structure, but nothing seems to work. When I leave the Sansa connect to charge, it says connected. Is there a known problem using Sansa with Rockbox? The only issue I can find on the forum is about changing the folder structure. Both Rockbox and MediaMonkey are great products, I just need to get them to work together.

My system is Window xp.