Avast 2015 has broken Chrome

[REDACTED]

Since updating to Avast 2015 I have been having constant difficulties with Google Chrome on two totally separate PCs both running Windows 7 Ultimate 64 bit.  Sometimes it will not open at all, sometimes it opens but immediately fails to respond and on rare occasions it will open and work normally.  Sometimes it helps if I disable all shields but not always.  When it does open I have to disable shields anyway in order to be able to use my personal digital certificate.

I have tried system restore to a date prior to the update when everything worked normally but it seems Avast is preventing this from working.  Is there any way I can revert to the previous version or am I going to have to dump Avast in favour of another AV program?

[Para-Noid]

Try a repair...Control Panel>Uninstall a Program>double click "avast">click "repair">reboot.
You may need two or three reboots.

FYI  Use a "lot" of caution when using system restore as you could do more harm than good.
This is especially so when doing a system restore in safe mode.

FWIW I have no issues with Chrome and v2015.

[REDACTED]

Today's Chrome update seems to have fixed what Avast 2015 broke except that I still have to disable Web Shield in order to use my digital certificate despite having entered the URL as an exception.

[rlweiner]

Since upgrading Avast 2015 Chrome is totally disabled. I can't load ANY pages -- they all say "Unable to access the network".  I'm using Firefox to post this, and it's working fine.  Chrome says it's up to date (version 39.0.2171.65 m).

This is a Windows 7 64 bit PC.

[Para-Noid]

What are you using for a firewall?
Is it set to allow Chrome?

[rlweiner]

I'm using ZoneAlarm.  It's set to allow Chrome, and Chrome worked fine before I upgraded Avast.

[Gopher John]

In ZoneAlarm, remove AvastSvc.exe from the list of programs allowed access to the internet.  Reopen Chrome and visit a website.  ZoneAlarm should ask if AvastSvc.exe is to be allowed.  Do allow it.  HTH.

[rlweiner]

Thanks, but there's no entry for avastsvc.exe in ZoneAlarm's application permissions.  I deleted every Avast entry but nothing changed and ZoneAlarm didn't prompt me to allow it when I started Chrome.  I then deleted every entry for Chrome and the results were the same -- no prompt to allow it, and it still can't pull up any pages.

I'm running a Malwarebytes scan to see if that shows anything.

[Para-Noid]

After deleting all avast entries in ZA a reboot may be required to force ZA to take an action.

[rlweiner]

Rebooting didn't do it, but manually allowing chrome.exe did. 

[Gopher John]

Are Avast shields currently enabled?

[rlweiner]

Before deleting and manually replacing the entry for Chrome in ZA, it didn't matter whether shields were enabled or not.  It seems like the problem was in ZA, but it happened immediately after updating Avast.  And it persisted even after reverting to a restore point before the 2015 update.

[Gopher John]

It does matter.  IF the WebShield is disabled, that is why ZoneAlarm didn't request permission for AvastSvc.exe.  It wasn't running.