OK, it's not just me. Here's what happens to me (Win7 64b):
Fireface UFX is working fine (using the USB interface - latest firmware update as of 14Feb 2011).
Shutdown laptop.
Boot laptop. No response from the Fireface settings on the taskbar. No response from the Totalmix button on the taskbar. No Fireface in Computer > Device Manager > Sounds, etc...
Unplug Fireface USB, plug it back in. UFX is detected and all is good!
Now, do the same as above but after shutting it down take the laptop to work where there is no Fireface. Boot laptop, and use as normal (but obviously with no Fireface). Shutdown Laptop to take back home.
Boot up with Fireface connected. Cannot access anything relating to the Fireface. Unplugging/replugging Fireface doesn't change anything. No Fireface in Computer > Device Manager > Sounds, etc...
To get it to work in this last scenario I must uninstall RME from Control Panel > Programs and Features AND go into Device Manager and manually uninstall and remove the drivers. At this point I can re-install the UFX from scratch and it works again.
Lesson - never boot up your laptop without the UFX connected!
I don't have this problem with anything else. Am I doing something wrong or is the UFX USB driver messed up?