Avast popup in new win 10 install

Windows 10 comes with its own AV-Windows defender and this looks like an Adware installed by Avast itself(you might have installed avast on your older OS).Remove Avast completly: 

Avast Uninstall Utility | Download aswClear for Avast Removal

Also confirm defender is set to ON(I assume no other AV product is installed) by going to Start>Settings>Update and security>Windows defender

I had the Avast software pop up on my computer at work running Windows 10 after it did a major Windows update.  I wondered if I missed the option to not install the independent software accidently.  My laptop at home running Windows 8.1 has updated, and Avast has been downloaded with a shortcut for install on my desktop.  This is NO accident.  Either Microsoft knowingly allowed this bloatware, or they have been hacked.

HEY MICROSOFT, which is it? 

I had the same problem.

AVAST installed itself WITH the automatic Windows 10 Update.

AVAST also turned off Windows Defender.

When I went to use the link provided to clean it from my machine, the AVAST uninstall utility wanted to do the uninstall in SAFE MODE and reboot my computer to SAFE MODE. 

NO WAY JOSE.  I'm not giving SAFE MODE access to foreign hacker criminals who found a way to hack into Microsoft updates.  I used CCleaner to uninstall it.  Then I went to "Run" and I typed in "regedit".  Then I searched my entire registry for "Avast" and I deleted every, single reference to it.  Even after uninstalling it, it took me 20 minutes to get rid of all the traces that Avast left behind on my computer.  Additionally, there was a suspicious file with "Avast" in the string that I could not get access to.  I ran CCleaner registry editor again, then RegEdit again, and it was finally gone. 

There's something fishy going on with that Avast hack.  Avast used to be run by honest people and was at one time a very good antivirus.  They didn't put a free version on computers without asking.  Now whoever is doing it, and that might be Avast or a hacker who is pretending to be Avast, is asking for permission to root files by trying to get access to your Safe Mode.

Good luck.  Here we go.  Another, major, hacking scandal.

@Timothy LeeDavis

Just meant as an info: Piriform (the maker of CCleaner etc) was bought by Avast in July 2017...

CCleaner bundles Avast AV as well as Google Chrome, a Google Toolbar and possibly other products....

Seems that they with their most recent CCleaner version 5.38 started with quite questionable and sneaky ways to "force" Avast AV on unsuspecting users...

Quite a few people here in Microsoft Community blamed their Avast "intrusion" on Microsoft when in fact they missed that sneaky Avast bundle when downloading CCleaner....

You might want to have a look at the respective threads in the CCleaner forum... I linked them in my recent post here:

Microsoft Update installed Avast Antivirus without my consent (page=1) (Jsssssssss December 16, 2017)