Keyboard and mouse stop working after exiting game

This started after the last client patch.
Symptom: Play game (rare I know). Log out and exit game. Within three minutes, keyboard and mouse will both stop functioning. This happens with different mice, different keyboards, be they USB or oldstyle PS/2.

Have not found any failed device driver or error log to help trace further. Only fix is to hot reboot or cold power cycle. Obviously this impacts all other activities and can cause data loss in other applications.

At the moment, I simply assume I'm going to have to reboot the system after I exit ... reminds me of old time DOS days and that isn't a good thing.