On Windows 10 Version 1607 for x64-based system with latest updates, Avast 17.2.2288 - updated 18 Mar 2017 - the Avast control panel or settings window or whatever you call it will not remain open. It starts to run with the window appearing, then immediately disappears, I assume because it crashes. The Avast Icon disappears for a short time from the “hidden icons” pop-up on the Windows task bar, then reappears.
Please try the following:Repair Avast:
Control Panel> Program and Features (Add/remove program)>Select Avast> Select Repair. Reboot when completed
https://www.avast.com/faq.php?article=AVKB204
If Repair doesn’t fix the problem, try the following:
Clean Install of Avast:
https://goo.gl/4Ptzkf
Thanks. The repair worked and the Avast control program icon style changed. Based upon the very recent date of the last core program update, it looks like the main program was updated, but its control (settings) program wasn’t. I base that upon the former presence of the old icon versus the new one now present.
On some systems it sometimes requires more than one restart for all changes to take effect.
Doing a repair forces a refresh of all installed items and another reboot.
Glad your problem is solved. 