Unable to uncheck admin

[Amph]

I have an Asus Zefone 2 Laser, now on Android 6.0.1, no rooted. After the upgrade to marshmallow I've installed Anti-Theft. Now if I go on Settings / Security / Device Administrators to uncheck Avast Anti-Theft, it says something like "Unfortunately Settings has stopped"." Pressing on "Ok", that comes back on Settings / Security. I can uncheck Android Device Manager all the way, but not Anti-Theft. And inside the app I cannot find any hint or setting or whatever that let me de-admin it. Have I missed somthing or I'm dealing with a bug? I really appreciate any help.

[Eddy]

As far as I know anti-theft must be a device administrator or it can not function properly.
If it doesn't have the highest rights, any malware can simply disable it and that would make anti-theft useless

[Amph]

Sure you're right, of course. An anti-theft app with no admin rights is pointless. But I need to remove AAT (temporarily by the way). Point is if I need to de-admin it in marshmallow, I can't right now. Anyway I had it in lollipop too - same phone - and it was fine.

[Eddy]

https://www.avast.com/faq.php?article=AVKB166

Try the alternative way.

[Amph]

Thanks Eddy for your replies but, as you can see, both are workable ways after AAT has been deactivated as a device admin. It looks like AAT doesn't let de-admin itself in marshmellow.

[Amph]

Ok guys, problem solved. Don't ask me why or how but uninstalling Avast Backup and wiping the cache partition did the trick.

[Eddy]

Nice to hear it is solved, but I find it a strange thing.

I wonder what would have happened if only the cache was wiped.
As both anti-theft and backup are separate applications they should not influence each other.
I really would like to hear about this from avast.

[Amph]

Yes, it would sound a bit strange to me too, Eddy. That's why it was some sort of last resource, but that is. As you can image, I've wiped the cache everytime I've uninstalled every app that I thought could interfere with AAT and his security permissions. So that wasn't the first time I cleared the cache from recovery mode. But I didn't mention I had activated the premium license of Avast Backup which had a bizarre expiration date, something like 1904. Maybe that is the problem, I don't know. Anyway I wrote this workaround as it could be useful to someone facing the same problem.

[Eddy]

I know avast backup is a old application, but that old...
avast must have been way ahead of its time

[REDACTED]

I am having same issue but uninstalling all avast software and clearing cache has done nothing, still get com.android.settings has stopped when trying to remove avast anti theft from administrators.