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firefox already running when trying to open firefox

  • 13 freagra
  • 28 leis an bhfadhb seo
  • Freagra is déanaí ó John99

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Problem started after upgrade to version 29.0.1 Using firefox, close browser. Later open browser again (same session on pc) but get message stating firefox already running, close firefox or restart pc. Each time I have checked to ensure firefox is not running so have to perform a restart of pc. Any suggestions please?

Problem started after upgrade to version 29.0.1 Using firefox, close browser. Later open browser again (same session on pc) but get message stating firefox already running, close firefox or restart pc. Each time I have checked to ensure firefox is not running so have to perform a restart of pc. Any suggestions please?

All Replies (13)

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Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall 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 and save the setup file to your computer.
  2. After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu).
  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 run Firefox's uninstaller or use a third party remover as part of this process, because that could permanently delete your Firefox data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be recovered unless they have been backed up to an external device!

Please report back to see if this helped you!

Thank you.

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Many thanks for quick reply. Having looked more into this latest release it appears that several things have changed and sadly not for the better. I am therefore going to try and obtain a copy of the ealier version rather than reinstall this new version in the hope that a newer version will be brought out that reverts back to the way Firefox was. Sadly if not then I shall have to find a new browser as sorry to say that Firefox seems intend on destroying the loyalty it had.

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Firefox is customizable. If you prefer the old design, switching back is easy

Athraithe ag user669794 ar

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You probably do not need to reboot the computer, but only kill the Firefox process and possible plugin-container processes in the Windows Task Manager.

Are you using "Clear history when Firefox closes" to clear some personal data when you close Firefox?

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Hi cor-el When this happens Firefox is not showing in task manager, hence I know it is not running. Firefox options are also set to clear history when Firefox closes. Message states close Firefox or restart pc and as Firefox is not running I have to restart if I want to use Firefox. As I have backed up all my settings etc I may well do a fresh/clean install over the weekend, but if so will install version 28 instead. Many thanks anyway for your suggestions.

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Try to disable "Clear history when Firefox closes" or try to set only one item to see which is causing this issue for you.

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This is not a cure but will make it easier if Firefox locks up.

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Many thanks for all replies. Problem still not solved, but at least firefox is now showing in task manager, so I can kill process. Going to do a clean install of previous version tomorrow, so hopefully that will resolve issue.

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First of all update to Firefox 29.0.1 if you have not done so already, that cures one of the reasons for this problem.

Secondly paste your trouble shooting information into your next post. Get that by going to the troubleshooting information page

  1. Easy method navigate to about:support by keying that into the location bar
  2. Use the button [copy text into clipboard] then paste it into your reply ( Ctrl + V usually works )
    (Oddly right now; for some reason; that is not actually working for me to copy full details ??!! )
  • Do you normally have Firefox set to clear History on exit ?

Athraithe ag John99 ar

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Already updated to Firefox 29.0.1 - problem only started with this update. Troubleshooting info pasted below. Yes I do have clear history on exit activated as I do not want to save browsing history.

Application Basics

Name: Firefox Version: 29.0.1 User Agent: Mozilla/5.0 (Windows NT 6.1; rv:29.0) Gecko/20100101 Firefox/29.0

Crash Reports for the Last 3 Days

All Crash Reports


Name: Ant Video Downloader Version: Enabled: true ID:

Name: avast! Online Security Version: 9.0.2018.95 Enabled: true ID:

Name: F.B. Purity - Cleans Up Facebook Version: 9.8.2 Enabled: true ID:

Name: Google Translator for Firefox Version: Enabled: true ID: translator@zoli.bod

Important Modified Preferences

accessibility.blockautorefresh: true browser.cache.disk.capacity: 358400 browser.cache.disk.smart_size_cached_value: 358400 browser.cache.disk.smart_size.first_run: false browser.cache.disk.smart_size.use_old_max: false browser.places.smartBookmarksVersion: 6 true browser.sessionstore.upgradeBackup.latestBuildID: 20140506152807 browser.startup.homepage: browser.startup.homepage_override.buildID: 20140506152807 browser.startup.homepage_override.mstone: 29.0.1 browser.tabs.warnOnClose: false dom.mozApps.used: true extensions.lastAppVersion: 29.0.1 font.internaluseonly.changed: true Comic Sans MS Comic Sans MS Comic Sans MS gfx.direct3d.last_used_feature_level_idx: 0 network.cookie.prefsMigrated: true places.database.lastMaintenance: 1400435107 places.history.expiration.transient_current_max_pages: 80480 plugin.disable_full_page_plugin_for_types: application/pdf plugin.importedState: true 2 plugin.state.npdeployjava: 1 plugin.state.nppdf: 2 privacy.clearOnShutdown.cookies: false privacy.clearOnShutdown.sessions: false privacy.donottrackheader.enabled: true privacy.sanitize.migrateFx3Prefs: true privacy.sanitize.sanitizeOnShutdown: true storage.vacuum.last.index: 1 storage.vacuum.last.places.sqlite: 1398265101


Adapter Description: NVIDIA GeForce GT 630 Adapter Drivers: nvd3dum nvwgf2um,nvwgf2um Adapter RAM: 2048 Device ID: 0x0f00 Direct2D Enabled: true DirectWrite Enabled: true (6.2.9200.16571) Driver Date: 3-4-2014 Driver Version: GPU #2 Active: false GPU Accelerated Windows: 1/1 Direct3D 10 Vendor ID: 0x10de WebGL Renderer: Google Inc. -- ANGLE (NVIDIA GeForce GT 630 Direct3D9Ex vs_3_0 ps_3_0) windowLayerManagerRemote: false AzureCanvasBackend: direct2d AzureContentBackend: direct2d AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0


Incremental GC: true


Activated: false Prevent Accessibility: 0

Library Versions

NSPR Expected minimum version: 4.10.3 Version in use: 4.10.3

NSS Expected minimum version: 3.16 Basic ECC Version in use: 3.16 Basic ECC

NSSSMIME Expected minimum version: 3.16 Basic ECC Version in use: 3.16 Basic ECC

NSSSSL Expected minimum version: 3.16 Basic ECC Version in use: 3.16 Basic ECC

NSSUTIL Expected minimum version: 3.16 Version in use: 3.16

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OK as a test try using Firefox when it is set to save History. If the problem goes away this is a known bug and hopefully it will be fixed soon.

The bug will stop people from using Firefox unless they know about the workarounds so it is some thing that should be given priority, but the earliest likely fix will be the next Release and that is weeks away. If the bug is dealt with as normal it will be months before it gets into the Release.

As far as I know you will be able to use Private Browsing windows ok, but you may need to close those before exiting from Firefox.

This particular bug can sometimes affect earlier versions of Firefox also. if you insist on using another version of Firefox until this is fixed consider installing an additional third party build

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Thanks john99, looks like cancelling "don't save history" has solved the issue for now. Let's hope this bug can be fixed soon.

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Note one potential fix is now in the very recent Firefox Beta 30b8 Initial reports suggest this fixes the issue. (Bug1005487#c38) If you have been suffering from this problem and want a fix now instead of in a few weeks time you may wish to download and install the Beta version of Firefox.

The beta version is effectively a release candidate but is only intended for advanced users or testers. I would be interested to hear feedback from those of you that do test this out.

Beta version download