MS Outlook 2013 destabilised

I frequently find that MS Outlook 2013 hangs on loading, at the point when it is loading Avast Antivirus add-in.
Even when it completes, it loads slowly while loading this add-in. I can live with this, but I can’t live with it hanging.
I can usually workaround it with a reboot but that is not good enough.

I propose to disable the add-in, but I do not know to what extent this would compromise my security. If someone emails to me a virus, is there an elevated risk that Avast will not trap it when the add-in is disabled? I still have “mail shield” on as active protection in the main settings.

Just what is it that this add-in does?

Thanks.