Was asked to make new post -
HP system - new out of box - removed mcafee using their tool.
I am trying to install IS (newest from avast site) - after install computer reboots and error says - did not restart proper.
Gives choices to remedy but the only one that doesnt keep me in loop is reformat/restore.
This paid version of IS and latest updates on Win 10. No specific errors given just wont launch windows. Runs fine until i install my avast!
Thoughts/Help?!
Download the avast removal tool:
https://www.avast.com/uninstall-utility
Download IS from here:
http://files.avast.com/iavs9x/avast_internet_security_setup.exe
Go into Safe Mode and run the removal tool > Reboot
Install IS and reboot again.
Safe mode check
Avast uninstall check
Reboot
Avast install - good
Insert license good
Reboot
Error - Automatic Repair -your pc did not start correctly choose restart or advanced options. Back to same stupid loop - uhg.
I dont understand why the issue - no conflicts should exist to create problems.
When issues like this occur at times I try rebooting several times and oddly sometimes things resolve themselves.
I would also manually check for any McAfee remains in ‘programdata folder’ and the Registry that could be causing conflict.
Just a couple of thoughts 
I used the mcaffee uninstall tool in safe mode, rebooted, used avast removal in safe mode rebooted, installs avast as admin - i cant even get safe mode to open just reboots and gives option again. I know it works on some (wifes laptop has it) but it refuses to interact for me and i cant determine a cause. If i wipe the drive and start over everything is fine until i install my avast -
Ill check to see if any remains of mcaffee are there but did not observe earlier in checks.
Windows 10 build 12240 latest file from avast in use
I’m sure you are getting the right tool but to make sure for Mcaffee
https://service.mcafee.com/webcenter/portal/cp/home/articleview;jsessionid=Y4ZL_MRHayC7D34X-zc4eob_RT2kgA3gFp335prKWE1-Pv76xruU!796569165!1381891474?articleId=TS101331&_afrLoop=1430966154703141#!%40%40%3F_afrLoop%3D1430966154703141%26articleId%3DTS101331%26centerWidth%3D100%2525%26leftWidth%3D0%2525%26rightWidth%3D0%2525%26showFooter%3Dfalse%26showHeader%3Dfalse%26_adf.ctrl-state%3Dx5ty1gasp_4
You may want to try to install just the Avast FREE version and during install choose CUSTOM and select only the shields…uncheck all others.
See if this works then you can always up-level features/version.
My thought is to see/isolate if issue is on baseline (conflict) with the A/V portion of Avast or one of the other tools/features.
ONLINE Installers
[b]http://files.avast.com/iavs9x/avast_free_antivirus_setup_online.exe[/b]
http://files.avast.com/iavs9x/avast_pro_antivirus_setup_online.exe
http://files.avast.com/iavs9x/avast_internet_security_setup_online.exe
http://files.avast.com/iavs9x/avast_premier_antivirus_setup_online.exe
OFFLINE Installers
[b]http://files.avast.com/iavs9x/avast_free_antivirus_setup.exe[/b]
http://files.avast.com/iavs9x/avast_pro_antivirus_setup.exe
http://files.avast.com/iavs9x/avast_internet_security_setup.exe
http://files.avast.com/iavs9x/avast_premier_antivirus_setup.exe