Boot scan problem

[Chiara98]

My Avast premium free trial recently ended but I kept the free version and I vaguely remember I changed some settings so maybe I scheduled a boot scan by accident.
Now this happened:

1) Today I started my pc and there was a blue error screen saying that I needed to restart, nothing happened so I turned it off using the start button.

2) I turned it on again and there was a "no bootable device" message so I turned it off.

3) I turned it on for the third time, there was a terminal window for a second and now I'm stuck with a "Avast Antivirus is loading..." and a loading bar on black screen.
If I press esc nothing happened, I can't even turn it off because if I press the start button nothing happens again.
It's been like that for almost one hour and I discovered the very existence of a boot scan like 15 minutes ago.
Is it normal that it takes so much time? Should I just wait hoping for the best? What can I do?

[MrDJ]

not sure.

the continuous loading screen is a known issue for months and talked about here with a fix to revert back to the old boot scan   
https://forum.avast.com/index.php?topic=320643.30

but, as youve now reverted back to the free version it could of messed something up so causing a blue screen.
if you can get back to your normal log in screen then open avast UI and see if you can find the geek area by following this https://support.avast.com/en-en/article/Use-Antivirus-Geek-settings/#pc as it says it applies to premium and avast free.

i had similar when it first happened but cant remember a bsod. hard turn off 2 times and turning on just continued with the loading loop.
try turning off, unplugging from mains for 15 minutes, then trying again. worth a go while you wait for others to advise.

[MrBald]

Ok, this is quite interesting but I had same issue and the fix was quite surprising. I decided to lower refresh rate of my monitor to standard 60hz, and then boot scan worked. I made account just to write this post, so I hope it will be useful to anyone.