Hi!
I have used avast pro for a while now and once or twice a month i do a boot scan.
today, a scheduled a boot scan but for some reason the scan failed and i got a “registry error” message.
when a
i force shut down and restart my laptop, same issue. its stuck on an endless loop.
i cant restore to a restore point and i cant also cancel the boot scan using the esc key.
Please help. i dont want to format my laptop.
thanks in advance for any information.
What os/sp?
What exact version of avast?
How long have you waited before the reboot?
Any other security (related) software installed? Or previously had installed?
I am having this exact problem; is there a specific reason and/or solution?
Try a repair:
Start > Control Panel > Programs & Features > Uninstall a Program > select Avast and click " Uninstall/Change ". Choose " Repair " and “Continue”.
Once the repair is completed, it is essential that you reboot even if it doesn’t tell you to.
Thank you so much; it worked! 
You’re welcome.