Yesterday I updated my old Theftaware to the new Avast version. From that moment, my phone never went in to sleep mode, causing the battery to drain by over 50% overnight. My normal usage is 2-3%. Which eventually caused my phone to shut down due to a low battery. When trying to restart the phone, the phone will almost finish starting up, but right at the last moment, the phone would freeze and restart, leaving only a few seconds to try and disable anything that was running. Eventually I managed to start Titanium Backup and uninstall the Avast version of Theft aware before the phone could reboot. I have now reinstalled the original version of theft aware from the market, and every thing is back to normal. No more reboots and the phone is going in to sleep mode as before.
My phone is a Galaxy SII. I also have root call blocker and green power installed and running at start up, but disabling these in the few seconds between reboots did not cure the problem, only the eventual removal of Avast Thetaware.
I just hope the final version of avast cures these problems.