https://bugs.winehq.org/show_bug.cgi?id=38114
--- Comment #16 from Erich Hoover erich.e.hoover@gmail.com --- (In reply to Nikolay Sivov from comment #15)
It could be that fixed drives only are listed automatically. USB stick doesn't appear for me either on Windows 7, but other partitions did and I didn't have to do anything.
They probably use some other way to detect the drive type then. I can resubmit the patch for this if people are ok with it (a quick look over it would be appreciated). I wrote it for my own personal drive configuration for Windows Steam a while back and after it dropped off the list a few times I stopped sending it in.