I have had a full scan running for 65minutes and yet the bar shows that only 6% of the scan has been completed. Is this normal for the pro version?
Have you made any changes to the pre-defined Full scan default settings ?
Have you done a Full scan before and was that similar in duration ?
Personally I feel a Quick scan is more than adequate as it covers the more critical files/areas, the Full scan goes to the next level of risk.
- With a resident on-access antivirus like avast, the need for frequent on-demand scans is much depreciated. For the most part the on-demand scan is going to be scanning files that would be otherwise be dormant or inert. If they were active files then the on-access file system shield would be scanning them before being created, modified, opened or executed.
I have avast set to do a scheduled weekly Quick scan, set at a time and day that I know the computer will be on. If for some reason my system wasn’t on, no big deal I will catch up on the next scheduled scan.
I see from your signature that you have SAS and MBAM are either of these resident on-access ?
If SAS Pro has resident scanning enabled try it disabled when avast is scanning.
Thank you for your reply. The scan is now complete and took 2hours and 55 minutes ie it took an hour to complete 6% and a further 2 hours to do the remaining 94%.
Its weird that this time frame has almost tripled, yet you have made no changes.
Have you defragged your Hard Drive recently ?
Check the settings in the Full and Quick Scan, More Details, Settings, Performance, ensure that the following are checked (enabled), Speed up scanning by using the persistent cache (default setting) and the Store data about scanned files in the persistent cache (not a default setting). The latter option should help in speeding up scans subsequently.
Thank you for your reply. In the slow scan, the store data was unchecked and now is, and in the full scan, the persistant cache was unchecked but now is. I have never ever tried to alter the settings or even accessed them before now.
Got an e-mail today:
‘Miroslav Jensic entitled [#QQR-920679 Slow Scanning’.
Did it come from this site?
Strange that the ‘Speed up scanning by using the persistent cache’ as it is a default setting.
Hopefully it will speed up future scans, but this may take a couple scans to have fully populated the persistent cache.
I don’t think so as the title seems to have a support ticket reference at the start of it. Though I have never needed to log a support ticket entry, I don’t know if that is the correct reference ID.
If it were from this forum then I would have expected it to be posted in the topic.
Googled Miroslav Jensic and up came Miroslav Jansic a Bosnian poet. Didn’t open the e-mail and transferred it to junk.
The question really is did you create an avast support ticked about this problem ?
Of course it may have been referred by one of the moderators, but that is unknown, but I have seen responses when the report to moderator link is used (but normally it is in the topic).
I have no recollection of having done so :-, but having a severe memory problem, that is par for the course for me.
:-[ :-[ :-[ :-[ David, I am really, really sorry. Went back and opened the deleted e-mail and low and behold, it was a support reply. I had raised a ticket and the reply was from Miroslav Jensic at Avast Software.
PS He provided the following link which fully explains the persistant cache and store data items:
http://blog.avast.com/2010/04/25/how-to-make-the-full-system-scan-6x-faster-in-10-days/
Am now running a full scan again after the changes to the persitant cache and the store data. The results from this mornings scan were as follows:
Run time: 2h.59m
Files: 462192
Folders: 54420
Data tested; 150.8GB
Will post the new scan result later.
No problem, easy to forget if there is a bit of a delay.
The instructions I gave are basically what is outlined in the link that they gave without being so long winded and related to the current avast version (as the article is quite old, but still relevant).
As I mentioned it may take a few scans to see the full benefit.
Post persistent cache and store data changes scan:
Run time: 1h.10
Files: 465222
Folders: 54657
Data tested: 151.5GB
Although the scan time was down about 60%+, the most surprising thing as far as I am concerned, was the speed which started off at around 80MB+ but ended mainly about 20-30MB (not that I know what difference this makes).
I generally don’t bother monitoring the scanning rate MB as that will change as the scan progresses and when it hits different file types and sizes. The only things that I monitor are the overall scan duration and the amount of data scanned (GBs).
So you are seeing a massive change when using the persistent cache, scan duration for what should be the same amount of data scanned.
That information in isolation is meaningless with no data/information to compare against.
My quick scan only takes around three minutes, that too is meaningless as my system specification is likely to be different to yours, as is the amount of data scanned and if you have made any changes to the default settings in the quick scan.
You can only really compare a scan duration against your own previous scans.
All down to you David, thank you so much! 
You beat me to it david, I was just going to say that :-[ :-[ :-[ :-[
You’re welcome.
You have to be fast on the avast forums, they are very active ;D