Scanning takes forever

[adscense]

I've been using avast for years now and very happy with it, at least till recently. I used to run simultaneous i.e. full system & folder scans on a weekly basis and it usually take about 1 hr 30 min for the whole process.

But lately when I run simultaneous scans, it takes like forever. I start the scans at midnight before going to bed and wake up in the morning at about 7-8 am only to find that the scan is only less than 5% complete and the speed is only less than 1-2 Mb/s. So I have to stop the scans. When I would run them separately it works sometimes but not always.

Then there is another time during folder scan, after 50 min it was 99% complete, but the last 1% took like forever and no completion in sight after 3-4 hours.

what is causing the problem? 

Thanks in advance for any answers.

[DavidR]

Firstly I can't perceive the need to run multiple scans as in many cases that will just be duplication in a lot of areas.

You don't say if you are also scanning archives (packers) nor if you have the Performance, scan priority set to High or more importantly what the persistent cache settings are. Yes you should use the persistent cache, but it is important to also Store data in the persistent cache, as that is how it gets populated to help speed scans.

- With a resident on-access antivirus like avast, the need for frequent (and multiple) 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.

####
What other security applications do you have installed ?

[adscense]

Thanks David for the reply.

The truth is I'm an average computer user and only have very basic and general laymen knowledge about antivirus. I don't have any technical knowledge about system security, antivirus, malware etc, can't even tell the difference between them. So to be safe I just thought 2 scans is better than one. 


Anyway, the point is I have no issues before when I run 2 scans at the same time till now. Also even when I run only folder scan now it takes me more than 3-4 hours and still see no end to the process.

Something must be wrong either with the program or my computer.

Avast is the only security software U use beside Windows Defender that was pre-installed.

You don't say if you are also scanning archives (packers) nor if you have the Performance, scan priority set to High or more importantly what the persistent cache settings are. Yes you should use the persistent cache, but it is important to also Store data in the persistent cache, as that is how it gets populated to help speed scans.

Honestly I have no idea what persistent cache settings are, but I use all the default setting of Avast.

[Pondus]

the easiest way to do this is to avtivate the screensaver scan and this will go all by itselfe

the scan will the start and stop with the screensaver, it will remeber where it stopped and start from that place again...unless you have rebooted the machine...


from the picture you posted in the first post, it looks as you are doing a custom scan with EVERYTHING selected....that is not necesarry

the default quick / full scan is plenty.....that is why they are default

and if you absolutely will do a custom scan..DO NOT use the "scan memory" setting as this often give some strange scan results

[DavidR]

Thanks David for the reply.
<snip>
Anyway, the point is I have no issues before when I run 2 scans at the same time till now. Also even when I run only folder scan now it takes me more than 3-4 hours and still see no end to the process.

Something must be wrong either with the program or my computer.

Avast is the only security software U use beside Windows Defender that was pre-installed.

It really is hard to say what might have changed on your system, as we know so little about it. OS, RAM, CPU, the quantity of data being scanned and if archives are being scanned. One major area is when this happened and what changed about that time, e.g. update from one version of avast to another, installation or update of other software, etc. ?

Personally I would disable windows defender, since it is a resident process there could be interaction between it and the scans. I have never been a fan of windows defender as I don't believe it brings much to the party. So when I bought my Acer win7 netbook to find it pre-installed in win7 I was pi**ed and more so when I found it 'couldn't be uninstalled,' only disabled I was even more pi**ed.

Then I would see if that made a difference, but I would certainly drop the multiple scans at the same time. Try just the Quick scan and see how long that takes, try the Full system scan on its own and see how long that takes (you would then have a comparison against how long it takes in the multi scan scenario). Lastly you could try Pondus's suggestion to use the avast screensaver scan to do a rolling scan.

You don't say if you are also scanning archives (packers) nor if you have the Performance, scan priority set to High or more importantly what the persistent cache settings are. Yes you should use the persistent cache, but it is important to also Store data in the persistent cache, as that is how it gets populated to help speed scans.

Honestly I have no idea what persistent cache settings are, but I use all the default setting of Avast.

The default setting is not to store data about scanned files in the persistent cache, so certain files that may have been added to the persistent cache won't be, so don't contribute to speeding up future scans, See image, I have mine on).

See image2 extract of avast Help Center about the persistent cache.

[adscense]

Thanks Pondus & David for the replies.

Let me take some time and go through them for a better understanding of what you are saying and try the recommendations. 

Thanks again for your time.

[DavidR]

You're welcome.