It's unlikely that Avast caused this problem. It seems that MS did not update an AuthCab file when it expired & this has caused ongoing update problems for some users. This remedy seems to have worked for a lot of this Forum users who have experienced the same problem.
"Windows update cannot currently check for updates, because the service is not running, You may need to restart your computer".
This is exactly the message you get when the AuthCab has expired. Doing the following seems to fix it:
The date on the computer has to be reset & to do that follow this:
To reset the date on the computer Right Click on the Clock at bottom RH corner of the screen, select Change Date & Time Settings, when that opens click on the Internet Time tab, Then select Change Settings, then untick Synchronise with Internet Time Server, be sure to tick OK, then select the Date & Time tab, Then select Change Date & Time & set the date back to 3 Dec 2017.
Then reboot the computer & then run Check for Updates in Windows Update, it should update to the 3 Dec. In some cases you may need to try an earlier date if the 2nd doesn't work.
Then reboot, reset Internet time Synch, change computer date to today's date, re run Check for Updates in Windows Update & it should check for Updates & came back with Windows is up to date, with the latest updates installed.
This method should retain all your Update History as well.
The reason for this procedure, is that Windows accesses an AuthCab during the start-up procedure that Authorises access to the Windows Update download site. This authorisation expired on 3 Dec for a lot of users & access get blocked to the Windows Update site.
By running the repair I listed above, resetting the computer date & rebooting provides access to Update site at which MS have now reset the expiry of that AuthCab which gets installed on your computer, so it can now download & install Updates. Of course it is then necessary to reset the date on the computer & re run Check for Updates to bring it completely up to date.
