Firefox will not open on Windows 10 no matter what I try. Is there a something that can fix this?
I tried contacting Windows 10 support and they were useless. It was working fine all day and suddenly wouldn't open.
தீர்வு தேர்ந்தெடுக்கப்பட்டது
This sounds like a file in your Firefox profile may be corrupt or invalid. To check to see if this is the case, you will need to create a secondary Firefox profile and test to see if you can open up Firefox through this profile.
This can be done by using the Profile Manager for Firefox that can be downloaded from the Mozilla FTP server. There is no installation required, as the program is contained within a ZIP file. Simply extract the ZIP file and run the executable file inside.
For steps on how to create a second Firefox profile, please refer to this support article:
Note: Do not delete the old profile because if it is corrupt you may be able to recover your bookmarks and some settings. For more information on how to do this, please read the Recovering important data from an old profile article.
Read this answer in context 👍 2All Replies (9)
Certain Firefox problems can be solved by 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.
- 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.
- After the download finishes, close all Firefox windows (or open the Firefox menu
and click the close button 
).
- Delete the Firefox installation folder, which is located in one of these locations, by default:
- C:\Program Files\Mozilla Firefox
- C:\Program Files (x86)\Mozilla Firefox
- Now, go ahead and reinstall Firefox:
- Double-click the downloaded installation file and go through the steps of the installation wizard.
- 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.
Please report back to say if this helped you!
Thank you.
It is possible that your firewall or other security software blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.
Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full, unrestricted, access to install for Firefox and the plugin-container process and the updater process.
See:
Wesley Branton said
Certain Firefox problems can be solved by 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.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. Please report back to say if this helped you! Thank you.
- 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.
- After the download finishes, close all Firefox windows (or open the Firefox menu
- Delete the Firefox installation folder, which is located in one of these locations, by default:
- C:\Program Files\Mozilla Firefox
- C:\Program Files (x86)\Mozilla Firefox
- Now, go ahead and reinstall Firefox:
- Double-click the downloaded installation file and go through the steps of the installation wizard.
- Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.
Yeah this hasn't solved my problem sorry.
Type about:preferences#advanced<Enter> in the address bar.
Under Advanced, Select Network. Look for Configure How Firefox Connects and press the Settings button. If you are using a proxy, make sure those settings are correct. If there is no proxy, first use No Proxy. If there is a problem, then try System Proxy.
Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options) key, and then starting Firefox. Is the problem still there?
Are there any error messages being displayed when you click to start Firefox?
In the Windows 10 task manager (Crtl + Alt + Del), can you see the firefox.exe process running in list of processes?
தீர்வு தேர்ந்தெடுக்கப்பட்டது
This sounds like a file in your Firefox profile may be corrupt or invalid. To check to see if this is the case, you will need to create a secondary Firefox profile and test to see if you can open up Firefox through this profile.
This can be done by using the Profile Manager for Firefox that can be downloaded from the Mozilla FTP server. There is no installation required, as the program is contained within a ZIP file. Simply extract the ZIP file and run the executable file inside.
For steps on how to create a second Firefox profile, please refer to this support article:
Note: Do not delete the old profile because if it is corrupt you may be able to recover your bookmarks and some settings. For more information on how to do this, please read the Recovering important data from an old profile article.
Wesley Branton said
This sounds like a file in your Firefox profile may be corrupt or invalid. To check to see if this is the case, you will need to create a secondary Firefox profile and test to see if you can open up Firefox through this profile. This can be done by using the Profile Manager for Firefox that can be downloaded from the Mozilla FTP server. There is no installation required, as the program is contained within a ZIP file. Simply extract the ZIP file and run the executable file inside. For steps on how to create a second Firefox profile, please refer to this support article: Note: Do not delete the old profile because if it is corrupt you may be able to recover your bookmarks and some settings. For more information on how to do this, please read the Recovering important data from an old profile article.
I created a new profile for Firefox and everything was up and running again fine! Thanks to all of you for your answers, I really appreciate the helpful community here. Have a good day Wesley Branton, cor-el and FredMcd. :)
I am glad to hear that your problem has been resolved. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution more easily.
Thank you for contacting Mozilla Support. If you have any more issues, please let us know.
When you are ready, we can start moving parts of your old data and Copy it to the new profile.
First; open your file browser to the New profile;
Type about:support in the address bar and press enter.
Under the page logo on the left side you will see Application Basics. Under this find Profile Folder. To it’s right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.
Second, open the file browser to the Old profile. You should see it on the directory "tree" in the first file browser. Right click on that folder and select Open In New Window.
Warning ! ! Only Copy the files you are told. We will avoid anything that might be the cause of your problems. Here is the list of files;
cookies: Do not bother. Cookies will be created when you return to the web site. However, you will have to log in everywhere.
extensions(add-ons): it would be better to download them fresh. +++++++++++++++++++++++++++++++++++++++++++++++++ key3.db and logins.json: These are the Password files.
persdict.dat: custom dictionary – words you added to the dictionary
mimeTypes.rdf: What to do with what type of file.
places.sqlite: History and Bookmarks.
prefs.js: Your settings. Note, this may be contaminated. +++++++++++++++++++++++++++++++++++++++++++++++++ Copy these files from the old to the new. You will get a message about the files already exist. Choose to over-write for each file.