I don’t boot my laptop very often, but it’s a Mac so it wouldn’t be comparable anyway.
I did a quick search and you’re not alone. One guy wrote this:
Personally I’d uninstall it and activate Microsoft Security Essentials (aka windows defender) and Malwarebytes Antimalware.
I had Malwarebytes on my machine but removed it. I didn’t see that it did anything for me. It might matter on Windows.
You could also see if there are any settings for Avira that will change how it scans on boot.
Thanks. I wrote all that stuff down because this is going to be one of those days.