Avast - is there a way to reign in aggressive web scanning?

rivre · 20 Oct 2017

I'm generally pretty happy with Avast (free) but it scans downloading files, even large .rar files, sometimes corrupting them. Whenever I download larger size .rar files I have to remember to disable Avast , otherwise the icon just runs nonstop the whole times it's downloading and the HDD grinds and the crc of the file sometimes says it's corrupted. As soon as I disable Avast the HDD settles down and the files don't get corrupted. It does the same thing when streaming video.

What can I do, short of disabling the "Web Shield" entirely (I'm guessing that's to blame?)?

- For file system shield, "scan all files" and "scan files when writing" are both unchecked. I've also added "*.rar" to the list of exclusions.

- For Web Shield, I can exclude URLs, MIME types, or processes, but I see no way to exclude file types. Under the "Web Scanning" option, I can select "scan all files" or "scan selected file types only". Currently it's set to scan all files. Under "packer" list of packed files it should unpack and scan, I have deselected .rar, .zip, and .7zip.

Yet it still insists on scanning large rar files as they are downloading. What do I have to do to stop this behavior. Scanning web files as I surf is fine, but I don't want it to scan .rar files when they are downloading - I will scan them myself manually when they are finished. Right now Avast is just corrupting my downloads and grinding my HDD when I stream and download and I need to find a way to stop it. If I have to just disable Web Shield entirely, then it seems I'm losing some important protection.

dalchina · 20 Oct 2017

Hi, I use Avast - the only irritating thing I've noticed (other than popups- being the free version) is that on some web pages there are links to certain sites which it warns about (usually a pair) then presents a large Window over the top of what I'm doing, which resolves to two I then have to close. Only had that starting recently.

Could you provide a link to one of the files you have problems with?

TairikuOkami · 20 Oct 2017

rivre said:

If I have to just disable Web Shield entirely, then it seems I'm losing some important protection.

If you have got a sandboxed browser with safe extensions and using a safe DNS, webshield is virtually useless.

rivre · 20 Oct 2017

TairikuOkami said:

If you have got a sandboxed browser with safe extensions and using a safe DNS, webshield is virtually useless.

I use Firefox (private mode) for most of my surfing. What do you mean by safe DNS?

dalchina said:

Could you provide a link to one of the files you have problems with?

It's all large files. Especially large archive files like .rar, .zip, and streaming video, since that's a constant stream of data. Basically, any time there's a constant stream of data downloading, Avast insists on scanning it all, constantly, while it's downloading. It tends to corrupt some of the files since it's scanning while it's being downloaded, also causing the HDD to make a ton of racket. When I disable Webshield, browsing is quiet. With it enabled, it makes surfing much noisier since every time I click a new link or open a new page it scans everything. I can live with that, but I'm trying to reign it in so at least it leaves the large downloads alone. But there seems to be no way for me to tell it "Don't scan large files" or skip files of a certain type in Webshield.

If I have to keep disabling it, it defeats the purpose of having it. I'm not going to disable it every time I have a download coming over or every time I stream a video.

TairikuOkami · 20 Oct 2017

rivre said:

What do you mean by safe DNS?

Default ISP DNS servers provide basic internet access.

Better DNS blocks phishing, malware webpages, some even tracking and so on.

Top 10 Best Public DNS Servers Fastest DNS Servers 2017

dalchina · 20 Oct 2017

and streaming video,

- can confirm I had no issues with that, for example.

while it's downloading. It tends to corrupt some of the files since it's scanning while it's being downloaded, also causing the HDD to make a ton of racket.

Please run a check on your disk... download and run Hard Disk Sentinel (trial) and post a screenshot of the result.

rivre · 20 Oct 2017

TairikuOkami said:

Default ISP DNS servers provide basic internet access.

Better DNS blocks phishing, malware webpages, some even tracking and so on.

Top 10 Best Public DNS Servers Fastest DNS Servers 2017

Oh, yeah, I use OpenDNS in my router.

rivre · 20 Oct 2017

dalchina said:

- can confirm I had no issues with that, for example.

Please run a check on your disk... download and run Hard Disk Sentinel (trial) and post a screenshot of the result.

There's nothing wrong with my HDDs. It affects both my main and working drives. It's just Avast mucking up my downloads. When I download some files via Jdownloader 2 the crc check fails when Avast is scanning them. With Avast webshield disabled I have no issues like this. It's clearly Avast.

eLPuSHeR · 21 Oct 2017

Abandon AVAST and get Windows Defender instead? You will be surprised that it works quite well. Newest version (Fall Creators Update) is even better.

But make sure you remove AVAST fully first. If you are not satisfied, you can reinstall it later.

AMDMan2016 · 21 Oct 2017

Been using Avast for last about 11 years, and never experienced that problem, but a clean install of Avast should solve it, and just use default settings, and Downloads should work properly again

Make sure to use avast clear uninstall tool, then reinstall, reboot after install, and should work perfectly, knows does here on every system.

Almost Switched permently to Defender after my clean install, but started feeling unsafe with Defender for some reason, or I used Avast so long, that i'm totally trust that program more than built in Defender