There is a compatibility issue between Firefox and AVG Antivirus.



8 years ago
3 years ago


(Reporter: john, Unassigned)





8 years ago
User Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/534.30 (KHTML, like Gecko) Chrome/12.0.742.122 Safari/534.30

Steps to reproduce:

I have a number of machines and for many years have used Firefox as the primary browser and AVG as the virus protection.
There is a problem with crashing and slow, incredibly slow performance. If you leave the browser up, return to a page in 1/2 hour or so, it takes what seems to be several minutes for the program to respond.  

Actual results:

If you have and open browser, or three or four, go away from the computer and then return 30 minutes or so and try to browse or continue on that page.  The browser goes "Not Responding" then after several minutes it either starts working, or crashes. 
Once back up, it works OK but slower.

Here is the issue I've found. and it doesn't matter if it is Firefox 3, 4, 5, or 6 they share the issue.  There is a compatibility issue with AVG AntiVirus specifically the Active Link Scanner module.  With it on, the problem is there, Firefox is a slug and crashes. Disable the module and the browser works as it should.

This isn't specific to one machine, I have 8 computers at home and another 8 computers in my office, and they all have the same issues with Firefox and AVG Anti Virus.
I don't have the issue with Chrome, IE8 or 9, Safari, Opera etc..  It is only with Firefox.  A search of the web shows that it seems to be a common issue for many users.  My simple work around before I did the work to isolate the cause was to use Chrome as my browser.
I'm sure it can be duplicated by loading AVG and Firefox on a machine, XP, Vista or Win7 don't matter.  Run the browser and enable the Link Scanner in AVG.  It should give you issue.  Disable it, and they go away..

Expected results:

It should not be affected by my anti virus software.  AVG, either Free or licensed copies..
Disable Link Scanner in AVG and Firefox is fine, enable Link Scanner and use Firefox and you have a troubled application that doesn't work correctly.
Please report to AVG.
Component: General → AVG AV
Product: Firefox → Plugins
QA Contact: general → avg-antivirus

Comment 2

3 years ago
Closing old bugs in the Plugins component. We aren't going to track issues in 3rd-party plugins in the Mozilla bug tracker. In addition, support for NPAPI plugins will be removed at the end of this year; for more details see the post at

If there is a serious bug in Firefox, it needs to be filed in the "Core" product, "Plug-Ins" component.
Last Resolved: 3 years ago
Resolution: --- → INCOMPLETE
Product: Plugins → Plugins Graveyard
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