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For 7.0, get popup saying "Can't load XRE extensions." Firefox fails to open.


On Win 7 system, loaded new version 7.0 of Firefox. When attempting to open Firefox, I get a popup that say's "Couldn't load XRE functions." Firefox won't open.

Chosen solution

I had the same problem. I am running Zone Alarm. Went in and changed the setting in the 'Internet Protected' part, turned off Browser Virtualization. And no more popups from XUL Runner. Firefox opens just fine.

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Additional System Details

This happened

Every time Firefox opened

This started when...

After installing v. 7.0

Installed Plug-ins

  • Adobe PDF Plug-In For Firefox and Netscape 10.1.1
  • Shockwave Flash 11.0 d1
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • Adobe Shockwave for Director Netscape plug-in, version
  • iTunes Detector Plug-in
  • Version 1.1.11, copyright 1996-2011 The VideoLAN Teamhttp://www.videolan.org/
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • Next Generation Java Plug-in 1.6.0_26 for Mozilla browsers
  • npFFApi
  • Office Live Update v1.5
  • The Hulu Desktop Plugin allows Hulu.com to integrate with the Hulu Desktop application.
  • 4.0.50401.0
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers


  • User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:7.0) Gecko/20110923 Firefox/7.0 SeaMonkey/2.4

More Information

Firefox won't open so there isn't any.

Question owner

The popup with the message "Couldn't load XRE functions." is coming from XULRunner.

karla_n_spike 1 solutions 1 answers

Chosen Solution

I had the same problem. I am running Zone Alarm. Went in and changed the setting in the 'Internet Protected' part, turned off Browser Virtualization. And no more popups from XUL Runner. Firefox opens just fine.

Question owner

Same here. Good catch. Have you let Zone Alarm know about this incompatibility?

Question owner

The problem with Zone Alarm and Win 7 did not occur on my XP laptop. Firefox 7.0 opened normally even with Browser Visualization turned on.

Arbyem 0 solutions 3 answers

Hi: I just posted a question regarding the same problem. I have not yet received a response. However, I just happened to try running Firefox 7.0.1 in Administrator Mode, and Firfox opened! I have recently performed an In-Place Upgrade of my HP dv9820 laptop from Vista Home Premium x64 to Win 7 HP x64, and upgrades to my Firefox (from 6.0.2) and, of course all of the many updates for Win 7. I also have Zone Alarm Extreme Security 2011, but I have yet to try the solution above from karla_n_spike. Until Mozilla provides a resolution such that Firefox 7.0.1 does not have to run from Administarator Mode, I will continue to do so. However, given that I receive the same error "XULRunner-couldn't load XRE function" whenever I activate a hotlink from an email or website (Firefox is my default browser), I will try changing my default to IE9. I would be grateful for any other insights into a more satisfactory resolution such that I could continue to use Firefox and my default browser. Appreciatively, Arbyem

camba78 0 solutions 1 answers

Also got Firefox to load normally after changing the setting mentioned. But I don't know how important the protection is which I am losing by switching this setting to "off." Haven't tried on my laptop yet.

Arbyem 0 solutions 3 answers

Hi again: I tried the "disable browser virtualization" In my Zone Alarm Extreme Security 2011, as suggested in this post stream: https://bugzilla.mozilla.org/show_bug.cgi?id=689719 but it did not resolve the problem For my work-around to the inability to use hotlinks via Firefox, I can also open Firefox running under the Administrator, and copy and paste the hotlink, but that is a kludgy process to have to conduct. Besides, I want the Zone Alarm Extreme Security protection in the "browser virtualization" area. I await a more satisfactory resolution from Mozilla. Appreciatively, Arbyem

Question owner

I agree. Mozilla needs to address this issue so that the Zone Alarm functionality can be used. This problem does not affect Sea Monkey, another Mozilla browser, or any other browser as far as I am aware.

Arbyem 0 solutions 3 answers

Thanks for the confirmation. I had to use the kludgy approach of copying and pasting the URL from my email to a Firefox webpage opened using the run as Administrator mode. Hopefully, Mozilla will resolve this embarrassing problem. I also hope that they resolve a similar incompatibility that prevents Firefox from permitting my RoboForm2Go program to operate by displaying its toolbar as an acceptable add-on. Arbyem

kestrels 0 solutions 1 answers

I also have the XRE problem with XP Pro. I'm pleased to hear that I'm not alone. I've no intention of altering Zone Alarm security settings. I have no problems using Chrome, IE or Safari. I expect Mozilla to address the issue.

Panthera 0 solutions 2 answers

Helpful Reply

This is from ZA - Of course, I'm running extreme!

We are beginning to send out auto updates for the Security tool bar (Conduit tool bar) and Web Security (Browser Virtualization, Site Check, Advanced download protection, etc...) This is a silent update

These are separate components that are integrated together.

Reason that we are late delivering compatibility for Firefox is that two different companies and development teams need to deliver both parts at the same time. But it not always possible that can be accomplish due to many issues not always we can control.

We are auto updating now for all paid products except for Extreme. (ZA Free is not updating also) We don't have an ETA for Extreme or ZA Free yet but when we do we will update this thread.

You can try to manually update the Conduit tool bar from there menu in the tool bar. You can also update Web Security from the setting section of web security in the ZA client.

We acknowledge the manual update does not always work. In these cases you will have to wait until the auto update gets delivered to your PC(s).

We hope this answers some of your questions and gives you a better idea how things work behind the scenes.

Also, check the version you're running. I clicked update and it said I was up to date. I went to the website and see I don't have the latest version. I don't know if it will help since I've got Extreme but I'd rather have the current version.

Modified by Panthera

Panthera 0 solutions 2 answers

I updated my ZA Extreme and I can now open 7.0.1 normally.

DavidBessire 0 solutions 2 answers

In attempting to upgrade to Firefox 8.0, I get the error message "Cannot load XRE functions" and although Mozilla Firefox 8.0 is shown downloaded into Programs and Features, it won't open. I tried to Run as Administrator and get the same error message. I am not using Zone Alarm but do have Avast Anti-virus, XoftSpySE, Ad-Aware and ParetoLogic PC Health operating.

How can I complete installation of Firefox 8.0 and use it?

DavidBessire 0 solutions 2 answers

I forgot to mention that I am using Windows 7 operating system in 32 bit.