AntiVirus affecting large zip downloads at high speeds?

(I hope I'm not too off-topic with this post)

I have a 1Gbit FTTP connection which works fine under normal daily use.

However, on several occasions, when downloading large (20GB+) zip files from Google (e.g. Google Takeout or Google Drive), the download fails at a random point after a good chunk of the file has been downloaded, with the browser reporting a "network error" as the cause.

Trying a new download of the large file results in a few bytes being transferred then it just sits there downloading at 1980s dial-up speeds, if that.

General browsing continues to be fine. But restarting the PC is the only way to be able to try the big download again.

It does not appear to be the browser. I've tried chrome and FF (and Edge).

The PC is more than powerful enough for literally anything imaginable (bar calculating the answer to Life, the Universe and Everything) and has 64GB of RAM. The Ethernet adapter is the motherboard's on-board Intel Gbit chip of one kind or another.

The router (Mikrotik hAP ac3) is more than powerful enough for anything ethernet-wise, and checking its CPU and memory usage (and its error log) during the download, nothing even breaks into a sweat.

My suspicion is currently falling on my AV because on two occasions after rebooting after a failed download, I have succeeded in downloading the file with no issues at all ----- but only after turning the AV off.

My thinking is that the AV may be, in some way, intercepting the download, unzipping in realtime, in order to be able to scan it for threats before it gets written to disk (or maybe as it gets written to disk), and maybe it just can't cope when trying to deal with a huge ZIP containing an awful lot of individual files coming down the wire at 800Mbits+. There were many 1000s of files in one particular download. Or something. I don't know how modern AV utilities work. Maybe they don't do anything of the sort, and this is a total red herring.

But because I don't have enough data points - two successes are not a smoking gun - I can't say for sure whether it was coincidence that switching off the AV worked. Maybe the download would have worked anyway on that particular occasion and the problem was something else entirely.

To make things more difficult to trace, I'm pretty sure that I've downloaded similarly sized files from non-google locations without problems, some of them may even have been zips. But the download speeds were never quite as fast (300 to 500Mbit) and the contents were never as complex (just a handful of files).

Anyway, if anyone has any ideas or maybe suggestions for something else to look at, I'm all ears.

Yes, this has been seen in data centres and corporate networks faster than 100 Mbps for years, on Windows, Mac and Linux. Many “home grade” AV products are less useful in a Win10/Win11 world, than they were back in the days of Window 95, or even Windows XP.

Many corporates have moved to fully utilise Microsoft’s Defender product, with the subscription add ons for central reporting and status. They have layered defences with various protections on email and web gateways.

If as a home user you use a mainstream email provider (MS outlook.com, Gmail, Yahoo etc); and keep your software up to date, and perhaps use an ad-blocker in your browser, then why bother with a third party AV tool? I think the home user AV industry is on its last legs.

What AV are you using?

I use Avast and I turn a lot of the extra stuff off as it slows the connection down.

Also sometimes after updating to a new version it can mess things up and cause connection issues too. I often have to uninstall it, clean the installation with their cleaner, then re-install it, for things to return to normal.

Just had he same issue with multiple network failures on a G drive zip file on another account, fixed it by copying the file across to my G drive and then downloading from my G drive. I only use Windows Defender.

In reply to a post by sfo32:

My suspicion is currently falling on my AV because on two occasions after rebooting after a failed download, I have succeeded in downloading the file with no issues at all ----- but only after turning the AV off.

I have in the past used Avast, AVG, Avira, and other free AV, last year having read lots of reviews and test site data i finally gave up and i now use Windows security on my PC and Laptop, give it a try it may solve your problem and you may be converted.

https://support.microsoft.com/en-us/windows/stay-pro...

Hi James
My Kaspersky "Internet Security" expired yesterday and I am now on a free extra 14-days.
My Win7 64-bit pc regularly downloads Windows Defender Antivirus (the current version of KB915597) and Windows Malicious Software Removal Tool x64 KB890830 - last one v5.109 on 11th January.

Do you think that I could do away with Kaspersky?

Thanks.

Cheers!

In reply to a post by Ancient_Mariner:

Do you think that I could do away with Kaspersky?

As you are using Win7 which stopped getting security updates in 2020, I would check with Kaspersky when they will stop doing updates for this operating system, it could be this year easily.

Browsers such as Chrome stopped supporting only this month. (15th January 2023)

It is really time to move on from Win7 I'm afraid, any third party security tool isn't going to protect you from malware when Microsoft has stopped issuing patches.

Edited by jchamier (Sun 22-Jan-23 11:46:07)

According to MS Answers Windows defender will stop receiving updates on Win 7 this month - so even more reason for them to move off Win 7 ASAP.