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Firefox not opening after crash

  • 6 replies
  • 1 has this problem
  • Paskiausią atsakymą parašė FredMcD

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My PC crashed and when I try to open firefox I get this error

XML Parsing Error: undefined entity Location: chrome://browser/content/browser.xhtml Line Number 732, Column 15:

             <toolbarbutton id="UITourTooltipClose" class="close-icon"


I saw this answer but I don't understand anything from it, English is not my first language. Will I lose my bookmarks and extensions? Do I delete the folders in program files or run the uninstaller? When running the installer there is an option to "restore default settings, remove extensions etc", should it be on or off?

I deleted the folder, ran the installer again and set the option to restore default settings off, and still can't open firefox. Can someone explain in simple terms?

Chosen solution

Thanks for the info. I reinstalled once with the "restore default settings" off and it didn't work, then started it firefox safe mode and disabled themes and extensions and alot of other things and it works now.

Skaityti atsakymą kartu su kontekstu 👍 0

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After, totally remove Firefox from your system in case any files were corrupted. Then re-install.

Let’s do a full clean re-install;

Note: Firefox comes in three or more folders on all computers. They are;

Maintenance: (Programs Folder) <Windows Only> Firefox itself: (Programs Folder) And two folders in the profile of each user on the computer for each Firefox profile for that user.

If you remove the Firefox folder, the user profiles would not be affected.

Download Firefox For All languages And Systems {web link}

Firefox ESR; Extended Support Release {web link}

Beta, Developer, Nightly versions

Install Older Version Of Firefox {web link}

Save the file. Then Close Firefox.

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

Windows: C:\Program Files C:\Program Files (x86) Note: Check Both Folders

Mac: Open the "Applications" folder.

Linux: Check your user manual. 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 remove any Mozilla or Firefox program folders. Do not remove the Mozilla Thunderbird folder if there is one.

Do Not remove any profile folders.

After rebooting the computer, run a registry scanner if you have one. Then run the installer. +++++++++++++++++++++++++++ If there is a problem, start your Computer in safe mode and try again.

How to Start all Computers in Safe Mode; {web link} Free Online Encyclopedia


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Thanks but... thats the answer I linked in the question and said I don't understand...

Do I run the uninstaller or delete the files in the programs folder? Do I say yes or no to "restore default settings and remove extensions?" when reinstalling firefox?


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Some uninstallers might leave something behind. So my instruction is to delete the Firefox folder in the programs folder.

Then use a registry scanner (if you have one) to remove any Firefox entries.

After rebooting the computer, run the Firefox installer.

Your profile is stored elsewhere on the hard drive. So when you run the new Firefox, it should be able to find it.


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Chosen Solution

Thanks for the info. I reinstalled once with the "restore default settings" off and it didn't work, then started it firefox safe mode and disabled themes and extensions and alot of other things and it works now.


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That was very good work. Well Done.

It could be the work of one of your add-ons, or it could be Hardware Acceleration. How to disable Hardware Acceleration {web link}

Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control> (Mac=<Command>) <Shift> A)

In the Add-ons Manager, on the left, select Extensions. Disable a few add-ons, then Restart Firefox.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All Of them.

If the problem continues, disable some more (restarting FF). Continue until the problem is gone. After, you know what group is causing the issue. Re-enable the last group ONE AT A TIME (restarting FF) until the problem returns.

Once you think you found the problem, disable that and re-enable all the others, then restart again. Let us know who the suspect is, detective.


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