I'm on Win8.1 and it appears I'm having problems with certificates.

Date/Time is ok (and updates at microsoft)!

I removed AVG 2015 (which I installed this week, and the problems started).


  • IE11 can not open google (or most https sites)
  • Google Chrome can't open https links (like logging on to some stack-exchange site). Some other https links (like google and youtube) work.
  • Norton removal-tool can't run: certificate problem (seems expired).

I currently installed FF (knowing it has it's own certificate-store), that at least helps me getting online..

I'm lost, please advise!

  • What do you mean "most" https sites? They should all work... I suspect the entire problem is AVG. Have you ran their removal tool? have you verified your proxy settings, which AVG would have changed, for its https spying capabilities to function?
    – Ramhound
    Apr 14, 2015 at 15:14
  • @Ramhound: yes, used removal-tool (was needed, couldn't use normal uninstall from AVG, it chocked on it's own Firewall, which it told us that was not in use as we needed to pay extra for that, as in, yes we even payed untill march 2016 for avg). edit proxy-settings in both chrome and ie ?? I'll check now. Apr 14, 2015 at 15:16
  • Sounds like you have an incomplete installation of AVG. You need to resolve that problem before anything else. You were better off just disabling the security feature and leaving AVG installed.
    – Ramhound
    Apr 14, 2015 at 15:17
  • @Ramhound: there seem to be no proxy-settings set in IE11. The AVG Removal-tool seems to have worked. What should I do to check AVG 'installation' ?? Apr 14, 2015 at 15:19
  • This can happen when your DNS uses something in-house (say at work, or over a VPN) or something of that nature as well, has anything else changed beyond AVG (router, other updates)? That said, windows has a good anti-virus built in now (windows defender/microsoft security essentials), installing multiples can cause strange issues. It is probably AVG, but wanted to throw out other things I have seen.
    – nerdwaller
    Apr 14, 2015 at 16:51

1 Answer 1


I'm on Win8.1 and it appears I'm having problems with certificates.
I removed AVG 2015 (which I installed this week, and the problems started).

Avast has a Web Inspect component (I think that's what its called), and it installs a Man-in-the-Middle (MitM) certificate like Superfish. See avast conducts MitM attack on users and encourages bad security practices.

To fix it, I would:

  1. Remove MitM certificates. See How to: View Certificates with the MMC Snap-in. Search for Avast and remove any certificates you find. Also search for koumbit.net and remove any certificates you find.

  2. Reset the browser. See How to reset Internet Explorer settings

There's also an Avast Removal Utility. I would run it and still perform the steps above. Avast could not be trusted during install, so I would not trust them for removal.

In the future, you should also consider running EMET on Windows. EMET has a security feature that attempts to detect folks like Avast and Superfish by pinning CA certificates and server certificates. (It has lots of other cool security features, too).

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