When I reviewed the HTC 7 Trophy I mentioned the only lock-up I had was then I tried to use it as an alarm clock.
At the time I suggested HTC is to blame, but it now appears it may be a more general problem. MobilityDigest writes that the issue has turned up on the HTC Mozart also, and seems to occur reliably when the phone is not plugged in and the alarm is snoozed.
Read more at MobilityDigest for their extensive testing on the issue, for which there is really no general solution at the moment, except to keep your phone plugged in at night.
Are our readers seeing this issue on other handsets, and on Samsung or LG handsets? Let us know below.