See if it is set to do a full scan every time it starts. If so, turn that off and schedule it for a more convenient time.
Or follow ArGee's advise - ditch it and use Windoze Defender. (It actually has gotten some decent reviews.)
I uninstalled Avira. That in itself was a job, as there were five components, which may explain why it took so long to boot up.
This morning it booted in less than seven minutes. :o])
As I was downloading Windoze Defender, I inadvertently downloaded Goober Crime. I couldn’t uninstall that fast enough!