I should add that, additionally, whilst Firefox is already running, loading Windows Media Player will then prevent any further Firefox windows/instances opening. Eg clicking links in Thunderbird no longer works. :(

I started Windows Media Player, then Firefox. I had no trouble (Win 7).

Download Firefox Full Version For All languages And Systems {web link} Save the file. Then;

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86) Mac: Open the "Applications" folder. Linux: Check your user manual.

• 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.

Look for, and rename any Mozilla or Firefox folders by adding .old to them.

After rebooting the computer, run a registry scanner. Then run the installer. If all goes well, remove the OLD folders when you are done.

This answer is basically just approaching spam level. Top 10 contributor? I don't think you even really cared about my question. Yes, I'm sure it does run for you, on your system, woopy. It runs for many of my users too, but on a few systems we see this issue. Now, have you got any really useful things we could do to try and debug this issue?

Have you done what I posted above?

Yes FredMcD, I've done "the above". And a lot more. Your generic response (mentioning Linux, whaa?) was obviously the first thing I tried. I'm a seasoned software developer and care for a business of over two dozen desktops, no newbie, and have many different configurations to compare against - but it's only a couple of systems showing this issue, and only in the past few months. And only with Firefox (no other apps hang). I'm looking for some real input on how we might diagnose and resolve this, not such basic level "works for me, try turning it off and on again" responses :) For example, might there be some way to launch Firefox and have it log how far its progressing as it starts up so we can get an idea about what's causing the hang? Developer builds we could run that include such features?

I am trying to help. Your abuse is totally uncalled for. Hailing Frequencies Closed.

I don't feel that your response was in any way genuinely helpful, or actually truly taking my original question in to account. Telling anyone that's asking a question on such a forum "works for me, so reinstall it" isn't really much help. Practically every single question could be "answered" that way.

Ian Jeffray,

Thanks for posting your issue, and welcome to Mozilla Support. This forum is run and driven mostly by volunteers, we're basically users like you and others trying to help you out. The people who answer questions here, for the most part, are other Firefox users volunteering their time (like me), not Mozilla employees or Firefox developers. Calling us out to be providing you with a spam response, basically tells us you're not valuing that you're at least receiving an acknowledgement and response to your question. You did not mention initially what you've tried or what troubleshooting you've done therefore, we need to start with the basics in order to help you since we are unaware of the background information. I understand that this is definitely frustrating for you and you'd like to get a resolution to your issue however, firing attacks at each other won't get us anywhere. Let's call it even, and get back on track so we can work together to make this work for you.

Hi Andrew,

I wasn't "attacking" anyone. Sorry if it seems that I did. I'm aware everything Firefox is volunteers, but such an obvious and generic sort of response was at least disheartening. [I'd be in trouble for giving such a response to a client at work!]

It's also mildly ironic that I've been unable to easily respond to these questions this evening by clicking on the links in Thunderbird because of this very issue. :)

My question did ask for ideas why this problem may be happening, not just for a "reinstall it and see if that helps" style solution -- as a software developer, I always want to try and find a root cause of an issue so that it may get fixed, not just masked for a while. As noted, this only happens on certain systems. And Windows Media Player isn't the only app that makes Firefox unhappy... it's just one which everyone should have, so seemed a suitable example of how such a commonplace app could cause Firefox to go so very bad. I guess this issue is rare. It could well be something to do with the additional software we install on our machines, but as I can't get the issue to appear on any given chosen machine, I have to address the issue on the ones where it appears -- which do have lots of other software installed. I'll just continue to dig; we've had to live with this for many months now anyway, but when it doesn't happen "on demand" and when it does, you just want get on with your work, so kill Firefox via TaskManager and restart it, it never seems a good time to start a diagnosis.

I'd paste the "about:support" info here, which I guess someone may consider looking at, but the output it generates is actually too large to be allowed in this response field.

Hi Ian,

Thanks for responding, and for your insight - it's greatly appreciated. I'm wondering if Firefox will open in Safe Mode if WMP is running, have you tried this yet? Let me know. Instructions on how to run Firefox in Safe Mode (not Windows safe mode) is attached below.

Try Firefox Safe Mode to see if the problem goes away. Firefox Safe Mode is a troubleshooting mode that temporarily turns off hardware acceleration, resets some settings, and disables add-ons (extensions and themes).

If Firefox is open, you can restart in Firefox Safe Mode from the Help menu:

• Click the menu button , click Help and select Restart with Add-ons Disabled.

If Firefox is not running, you can start Firefox in Safe Mode as follows:

• On Windows: Hold the Shift key when you open the Firefox desktop or Start menu shortcut.
• On Mac: Hold the option key while starting Firefox.
• On Linux: Quit Firefox, go to your Terminal and run firefox -safe-mode
  (you may need to specify the Firefox installation path e.g. /usr/lib/firefox)

When the Firefox Safe Mode window appears, select "Start in Safe Mode".

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, theme, or hardware acceleration. Please follow the steps in the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article to find the cause.

To exit Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help others with the same problem.

Thanks, and I look forward to hearing from you soon!

Hi Andrew, Had already tried this several times too. It didn't help, unfortunately. :( As noted above, even a really clean install from scratch with no add-ons installed still exhibits the problem. Willing to blame "something else" on my systems causing this, but it's only Firefox that has any noticable issue.