We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

FF won't start after installing an MLS Seattle theme

more options

When I opened FF this morning I saw on the FF home page a message about it is time to change my theme. So, I thought I would give it a try. I installed the MLS Seattle Sounders theme and then getting the message to restart FF. So I restarted, but now FF will not open. I can see that a FF process is running in the Task Manager.

I tried restarting my PC [I'm running W7P SP1] with no success. I also uninstalled & reinstalled FF with no success.

Any help would be appreciated and thanks in advance.

K

When I opened FF this morning I saw on the FF home page a message about it is time to change my theme. So, I thought I would give it a try. I installed the MLS Seattle Sounders theme and then getting the message to restart FF. So I restarted, but now FF will not open. I can see that a FF process is running in the Task Manager. I tried restarting my PC [I'm running W7P SP1] with no success. I also uninstalled & reinstalled FF with no success. Any help would be appreciated and thanks in advance. K

Isisombulu esikhethiweyo

Hi Keit.

According to the theme reviews, it's broken. To disable it, Try Firefox Safe Mode. 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 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".

SafeMode-Fx35

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.

Funda le mpendulo kwimeko leyo 👍 0

All Replies (1)

more options

Isisombululo esiKhethiweyo

Hi Keit.

According to the theme reviews, it's broken. To disable it, Try Firefox Safe Mode. 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 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".

SafeMode-Fx35

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.