Anyone noticed Chrome slowdown/lag sice Avast 25.5?

Hi, especially when I’m using uBlock Origin Lite, the whole browser becomes slow and laggy. It’s better without the extension, but still not as smooth as before. This started happening after I updated Avast to version 25.5. Has anyone else noticed this?

In Chrome task manager, I see CPU usage over 100% when loading pages.

Also behaviour of this is strange, one day browser lag a lot, next day works normally and next day lags again.

Reinstallation of Chrome and removing “User Data” folder not solved my issue.

First, I’m an Avast user and not an Avast Team member.

I don’t use Chrome, but I do use uBlock Origin Lite and uMatrix, using the Firefox browser and I’m not experiencing this.

My system specs are below my post.

This is not uBlock Origin Lite issue, because browser is slow and laggy even without extensions. With extension it is only more noticeable. What else than Antivirus can cause high cpu usage during page loading?

Today I can confirm, this is not only issue only on my PC. I tried Chrome with Avast installed on different PC and Chrome lags the same way. Please fix it. I use Avast 25.5 on Windows 10 64 bit 22h2

You’re not the only one to use the Chrome-Avast 25.5 pair and I haven’t seen any other messages about a widespread problem. I’m more inclined to think that a third party is configured identically for your 2 devices and is slowing you down.
For example your network or your DNS(try to change them),…

Chrome lags even when I’m browsing the Chrome settings, so this issue is not related to DNS. This forum seems abandoned—no one uses it anymore because it doesn’t work properly. The Avast team also no longer communicates here. I haven’t seen any release notes for version 25.5.

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I have figured out it has something to do with WebShield and Chrome. When I have a web page that doesn’t want to load, I turn off WebShield (typically for 10 minutes), then go back to the previous page (or restart Chrome) and try again. Usually the page will then load right away. When WebShield restarts, those pages will load fine the next times I go to them, but sometimes it seems a permament fix and sometimes the problem reoccurs some time later. It seems to mostly affect account pages, like my Amazon, banks and credit cards; all pages that I visit frequently.

Also I found another strange behaviour. Each time is Chrome updated, that day it works perfectly, but next day is slow and laggy again.

Also when is Chrome affected by Avast slowdown, Unicredit online banking shows blank page. When Chrome randomly works normally, this online banking works normally too.

My understanding is that this has been an issue since 25.3

Still not fixed in 25.6. Chrome is slow and UniCredit online banking not work!

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Summary:

Chrome works normally for about one day after each update to the new version, next day is slow again.

After updating Avast to the new version (25.6), Chrome also worked fine for one day, but the next day it was slow again. Reinstalling Chrome, including deleting the “User Data” folder, did not solve the issue.

The problem with Chrome first appeared when Avast version 25.5 was released. When Chrome is affected by Avast’s behavior, UniCredit online banking shows a blank page.

No Chrome extensions are used, but when they were enabled (e.g., uBlock Origin Lite), Chrome becomes even slower, to the point of being unusable.

System Info:

  • OS: Windows 10 64-bit, version 22H2
  • Antivirus: Avast Free 25.6.
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People have been having issues since 25.3 I believe. It’s why I still haven’t updated from 25.2

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I see you have brought it up in the latest release notes for Avast 25.6 hopefully that will draw a response.

Still not fixed in 25.7. and no one from Avast team ever communicated since I first reported this. Great support.

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Still not fixed in 25.8.

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Still not fixed in 25.9.

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Hey Avast employees? Any word? You seem to be responding in other posts about other stuff. Gonna fix this or are you all confused too? Or you don’t care?

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Hi @Dinobot2 and others, I’m sorry to hear about this issue and I apologize for not responding sooner.

Could you please capture a short video showing the issue, and how it behaves when Web Guard (Web Shield) is temporarily disabled?

We might also need to gather logs from the device, but it would help if we first had a video showing the issue.

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As I mentioned earlier, every page loads slowly, and with uBlock Origin Lite enabled, it’s even slower. This isn’t just a single-PC issue; I’m experiencing the same problem on computers running Windows 10 and 11 with Avast installed. Occasionally, after Chrome is updated to a new version, everything works perfectly for a day or two. However, after a few restarts, the problem reappears.