Author Topic: What happened to Avast! - time to complete a full virus scan increased by 113%  (Read 7790 times)

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Offline WebMaximus

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I always do a full scan of my computer Fridays and since the 17'th of Feb the time to complete the full scan has increased by 113% from about 53 minutes to 1 hour and 53 minutes.

The amount of folders, files and data is pretty much the same so whatever is causing this seems to be in the latest version(s) of Avast!

Hope there's a solution to this, seen others reporting the same thing.

Offline igor

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I always do a full scan of my computer Fridays and since the 17'th of Feb the time to complete the full scan has increased by 113% from about 53 minutes to 1 hour and 53 minutes.

The amount of folders, files and data is pretty much the same so whatever is causing this seems to be in the latest version(s) of Avast!

Strange... was there anything detected during the scan?
Did you change any settings of the full scan (not necessarily now, possibly some time ago), or is it on default?
What version of Avast do you have? Did you possibly update to the new version in the week before Feb 17?

Hope there's a solution to this, seen others reporting the same thing.

Where are others reporting the same thing?
Thanks.

Offline WebMaximus

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The first time I noticed this on the 17'th of Feb a number of issues were reported of which I'm certain they were all false positives. However I didn't use the files affected anymore so I decided to delete them just to make sure. Here's a screenshot of that scan but a bit hard to see due to the bad 4K scaling in Avast.



Today I had an issue reported as well and not sure if it was a false positive or not. The file triggering the alert was a file in my recycle bin called $ROM093N.adi where the threat reported was Win32:Hupigon-ONX [Trj]. I decided to move the file to the chest thinking I might want to investigate it further and it looked like Avast! was able to successfully carry out the action I asked for but when I later checked my virus chest it was empty?!

I also find the new GUI to be a bit confusing not really letting me know when an action has been completed...in this case moving the suspected file to the virus chest. Instead I had to manually press the 'Back' button and I could only assume the action had completed successfully.

I then decided to restart my computer and do another full virus scan and this second scan came out blank with no reported issues and it took just as long as the first one just under 2 hours vs the normal just under 1 hour.

I'm pretty sure this started with the latest version of Avast and the new GUI. Never saw this issue with the previous version(s) of Avast!

Here's another guy reporting very slow scans recently -> https://forum.avast.com/index.php?topic=197802.0

Sorry, forget to comment on settings used for the full scan. Nothing changed in there as far as I can remember. What I did try was to enable all settings found under the performance section on the settings page and I also changed the prio to high but all to no avail I'm afraid.
« Last Edit: February 24, 2017, 05:52:50 PM by WebMaximus »

Offline skanungo2007

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Yes it is true for me also. Scan time did increase a bit. A lot of time is wasted showing 'initializing".

Offline WebMaximus

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Thanks for your input and if in your case the scan time only increased a bit I guess you should consider yourself lucky since in my case it increased by more than 100%  ;)

Offline WebMaximus

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So will full scans take this long now or did you identify any issues that could have caused the increased scanning time in latest version(s) of Avast?

Offline Para-Noid

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Scan times are taking a bit longer.
That said, scan times will significantly decrease as you populate the persistent cache.
Just be sure you are using the populate the persistent cache in your scan settings.
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Offline bob3160

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Scan times are taking a bit longer.
That said, scan times will significantly decrease as you populate the persistent cache.
Just be sure you are using the populate the persistent cache in your scan settings.
It's set that way by default. :)
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Offline DavidR

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Scan times are taking a bit longer.
That said, scan times will significantly decrease as you populate the persistent cache.
Just be sure you are using the populate the persistent cache in your scan settings.
It's set that way by default. :)

I don't believe it is, some considerable time this  'Speed up scanning by using the persistent cache' was checked by default but the ''Store data about scanned files in the persistent cache'' was unchecked. I had to check this item some time ago (for the Full and Quick scans, the Smart Scan doesn't appear to have any settings icon. I always check it is enabled after a program update.

I just checked the various scan settings and some of them still didn't have it enabled by default. Now that was the USB/DVD scan, the Folder scan and the boot-time scan. There might well be a reason for that, but I can't see why some would be checked and others not.
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Offline bob3160

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I don't know what settings you have your screen shot. I referred to this:
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Offline DavidR

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I don't know what settings you have your screen shot. I referred to this:


Bob your image is for the file system shield and not on-demand scans which is essentially what the OP is saying is taking too long or much longer.

Quote from: WebMaximus
I always do a full scan of my computer Fridays and since the 17'th of Feb the time to complete the full scan has increased by 113% from about 53 minutes to 1 hour and 53 minutes.

My image is from the various on-demand Scan settings in the AvastUI > Protection > Antivirus > Other scans.
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Offline bob3160

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I stand corrected. Probably because for me the on demand scanning isn't really needed if you have a clean system.
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Offline DavidR

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I stand corrected. Probably because for me the on demand scanning isn't really needed if you have a clean system.

I too rarely use it, mainly in relation to helping in the forums ;)
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Offline WebMaximus

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Thanks for your input guys!

I've been using Avast for a very long time so I'm well aware of the persistent cache settings and I made sure the one populating the cache was checked at least once since I started having this issue but didn't notice any difference I'm afraid.

Maybe a bit over the top running manual scans for most people when you have real-time scan active but I'm extremely careful with my system since it's a very complex one taking weeks to setup so I don't take any chances.

Also I have areas of my system excluded from the real-time scanning for performance reasons making it even more important to have these areas scanned manually every now and then in my case once a week.

Clearly something changed in the latest version(s) of Avast as already mentioned because I've been running the exact same scanning method for years using Avast and with pretty much the same kind and amount of data on my computer and now all of a sudden it takes more than the double amount of time to complete.

I hope we'll see this addressed swiftly. If not maybe it's time to start looking for alternatives.

Offline DavidR

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If this was a clean install rather than an update from the UI or an install over the top of your existing avast version, then it may be possible that the persistent cache was cleared.

If that were the case it could take a few scans to actually populate the persistent cache.

Also as Igor was getting at, if there were detections during the scan, that would have a profound effect on the scan duration. When a detection is made avast goes into a paranoid (for want of a better word) sensitivity and this would prolong the scan.

I had previously done some test scans and watching the scan % progress, when a detection is made you see the % scanned drop considerably. I have seen it drop from around 69% back down to 24%.
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