Hi, it may be that your security software - or some part of it, is causing this, so disable it to test.

Do other browsers/programs start normally? If so, try performing a Clean reinstall. This means you remove your Firefox program files and then reinstall Firefox. This process does not remove your Firefox profile data (such as bookmarks and passwords), since that information is stored in a different location.

To do a clean reinstall of Firefox, please follow these steps: Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from mozilla.org (or choose the download for your operating system and language from this page) and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (or open the Firefox menu and click the close button ).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
   • Mac: Delete Firefox from the Applications folder.
   • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

More information about reinstalling Firefox can be found here.

WARNING: Do not use a third party uninstaller as part of this process. Doing so could permanently delete your Firefox profile data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be easily recovered unless they have been backed up to an external device! See Back up and restore information in Firefox profiles.

Be sure to delete the Firefox installation folder as above.

Please report back to say if this helped you!

Thank you.

Hi Scribe,

Thanks for the answer, other browsers work fine, in windows safe mode firefox works too.

I have tried to remove and re-install, but I'll do it again following your exact sequence, I removed it using the windows uninstal function and then deleted the folder.

I'll let you know the outcome.

Please install the Extended Release Version if not already https://www.mozilla.org/en-US/firefox/organizations/all/ since we have no info on anything as to what you are running on the old Machine. You may want to dig through the registry also and delete all entries you can find. Note : You have possibly reached the limit of what that machine can do. It is possible to use Driver Max (or) and update Motherboard Drivers and Chipset but there are risks.

As for the machine you came in on says Running newest Firefox... That means nothing to us. Too many people think they are running newest release and are not. Newest is Firefox 56.0.2 https://www.mozilla.org/firefox/all/ Note Firefox 57 Quantum release date Nov 14th https://www.mozilla.org/en-US/firefox/quantum/ Note : all Legacy Extensions will be disabled or removed.

Note : Update your Flash as your running a security risk ver 26 Flash Player Version: 27.0.0.183 https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only>

Please let us know if this solved your issue or if need further assistance.

Hi PkShadow,

I did what scribe said, didn't solve it, then I deleted everything again including the profile folder and the result is the same, it works in windows safe mode but not in regular mode.

I'll try to check the registry tonight and try the extended release.

I assumed I have the latest version since I downloaded the latest version from the site. I also assume the machine is not on his limit since firefox worked fine 2 weeks ago and has no problems running chrome/edge/opera.

Thanks for your time and effort!

Regards, Sven

Your System Details shows;

User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0

https://support.mozilla.org/en-US/kb/how-reset-default-user-agent-firefox

http://www.howtogeek.com/113439/how-to-change-your-browsers-user-agent-without-installing-any-extensions/

You can find the full version of the current Firefox release (56.0.2) in all languages and all operating systems here:

• https://www.mozilla.org/en-US/firefox/all/
• https://www.mozilla.org/en-US/firefox/56.0.2/releasenotes/