I’m running Internet Security. Once a week I have a scheduled full scan. It runs to 99%, then a window pops up and says “scan cancelled”. When I click on details, a new Smart Scan runs. History shows the full scan completed successfully. How do I know the full scan is doing anything. This has happened the last 4 scans.
As has been told in other threads already, that is a bug in displaying the percentage.
The scan does finish.
As mentioned, a known bug (GUI) awaiting squashing, the scan should/does complete, just check the Scan History to see if the entry is there for the scan.
“As told”, “As mentioned” - I did a search of the forum and did not get any results. If I had, I wouldn’t have bothered you.
Unfortunately the forum search is not great unless you hit on a sweet spot, the longer the search string is the more unrelated topics come into it.
There are times when it is better to use google or another external search engine and using the site search function.
Yes, a google search is faster and more reliable than a forum search.
Better use something like this next time on Google :
site:forum.avast.com
Same problem here on half a dozen systems, all W10, some Creators Update. 
And what exact avast version ?
Hello I’m running Avast Premier Version 17.4.2294 (build 17.4.3482.0) says 99% canceled on scan. I know its been happening for a while for others as well but I’ve had a few updates now and its still happening. I’m using Windows 10 creators update
Hi, sorry I never got a notice you posted here.
Avast version 17.4.2294