So I decided to go to town and copy a sizeable chunk of my music collection onto the N9 using WinSCP (yes, my media center PC runs Windows!) only to find that I'm unable to copy any files containing non-ASCII characters (umlauts etc). I get a "badly formed packet or protocol incompatibility" error. Never mind I thought, I'll just use USB to sync the missing files. But oh no, it's never that easy is it!? It seems something is keeping files open in MyDocs even after a reboot and all I get is "Can't connect to USB while your mobile's memory is in use". Double snafu!

What is going on here? I'm beginning to lose some of my warm feelings towards this phone...

H... help? Help! HEEEEEELP!!!

If you copied tons of music, the phone is probably scanning them. That might take a while. I guess giving it some time and trying again later would be the best course of action right now.

I don't think that the protocol layer should be affected by any special characters in the data, but it might depend on the software you're using. I used WinSCP many years ago but I think (hope) there are better alternatives for Windows users at this point. Maybe try Filezilla, or PuTTY SCP (PSCP) if you are not afraid of the command line.

impact may be right about why MyDocs is not available over USB.

Many thanks guys, will try FileZilla and also wait and see if MyDocs has become available again!

Indeed it seems you were correct, after waiting a few hours I tried again and mass storage mode worked as normal again. Good to know this for the future, many thanks!

Yep, tried FileZilla and not only was I able to transfer all files (regardless of filenames), I also got much better speed, about twice the transfer rate of WinSCP. Thanks for the tip!