The screen on my favorite Windows Mobile 6.1 device became miscalibrated. At first glance, nothing major: go into screen settings and choose calibration.

However, after every calibration attempt, the screen returned to the previous screen and calibration started again…

Changing one registry entry helped:

HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\TOUCH\MaxCalError

from 7 to 200.

Found, of course, on the MoDaCo forum: http://www.modaco.com/topic/298247-screen-calibrate-in-loop/page__st__20