Once in every 15 or 20 boots into Mint 6 x64, my usb wireless adapter does not power up. I'm using a Zydas WLA-54L (when I was still using Windows, vista identified the chipset as an Atheros ar5007ug). I'm not sure if Mint is not seeing my adapter or if it's a more general usb problem.
When the problem occurs, I restart the computer but immediately after leaving the grub menu I get an error message that flashes by too fast to read and the computer automatically reboots. This works but when I get to the desktop I find I've lost not only my wireless adapter, but also my wireless keyboard and mouse. A hard shut down and reboot clears the problem.
This never happens in the 32 bit version which I've been running exclusively on two computers for almost six weeks and dual booting for three weeks before that.
It it a minor glitch in a great OS but it is somewhat annoying. I think I'll stay with Felicia 32 bit for now because of this and other considerations.