This is the typical sign that your dvr has locked up - there is no way to recover except by reboot. From what I am reading on the 622, they run very hot and need lots of air and in fact 622 owners that frequent here are adding external fans to their 622's to get the temps down. I have been reading about this since I opted to upgrade to 622 myself and those who add the fans have been able to eliminate a lot of the troubles the 622's have been having.