I’ve been an avast user for about 8 years now. I have been getting the same thing on my main desktop system now for about 4 months. Basically since 2 avast engine updates ago. System is running windows 7 home premium and is an I7. I have a laptop, and a netbook both running windows 7 home premium that this doesn’t happen to for some reason. I’ve tried repairs, uninstalls / reinstall, clean installs and still get the issue. It’s becoming very annoying to see it happen almost every day at boot up. I’ve considered leaving the system on all the time or just putting it in sleep mode as it doesn’t happen if I do that. I’ve noticed in event viewer that if I get the popup annoying popup on bootup, the prior shutdown I get the following error.

Event ID 1530

Windows detected your registry file is still in use by other applications or services. The file will be unloaded now. The applications or services that hold your registry file may not function properly afterwards.

DETAIL -
3 user registry handles leaked:
Process 1312 (\Device\HarddiskVolume3\Program Files\AVAST Software\Avast\AvastSvc.exe) has opened key
Process 1312 (\Device\HarddiskVolume3\Program Files\AVAST Software\Avast\AvastSvc.exe) has opened key
Process 1312 (\Device\HarddiskVolume3\Program Files\AVAST Software\Avast\AvastSvc.exe) has opened key

I also find that readyboot has been giving the odd error since the last 2 avast updates.

Event ID 4

The maximum file size for session “ReadyBoot” has been reached. As a result, events might be lost (not logged) to file “C:\Windows\Prefetch\ReadyBoot\ReadyBoot.etl”. The maximum files size is currently set to 20971520 bytes.

My system had neither error until avast was updated a few months back during a normal update process.

Hope this info helps the programmers shed some light on the issue. As i’m puzzled.