Two avastUI.exe entries in Task Manager - Comment from avast team member.
The first AvastUI.exe instance is main GUI application, the second instance is for displaying web-content inside GUI (main page) or for popups with web content.
Some have found that when clicking other options within the secondary avast window which downloads other on-line date results in another avastUI.exe. Clo=sing these windows results in dropping down to the two instances that you see.
Interestingly on XP Pro OS you only see 1 instance of avastUI.exe, isn't progress wonderful
However, if you open a window from the avastUI, then I get the second avastUI.exe. If you open the account section in the avastUI, then I get two avastUI.exe entries presumably because it is getting data from more than one location.
At the moment I can't test further as I got a 502 bad gateway error displayed - but that then dropped one instance of avastUI.exe. Going back to the main UI drops it back down to one instance.