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.

Avatar for Username

Buscar en Ayuda

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

Este tema ha sido archivado. Haz una nueva pregunta si necesitas ayuda.

Firefox will not start. Displays XML Parsing Error: undefined entity?

  • 2 respuestas
  • 2 tienen este problema
  • 22 visitas
  • Última respuesta de Gunmetal

slotpilot4
slotpilot4
more options

Try to start firefox and a white screen pops up with:

XML Parsing Error: undefined entity Location: chrome://browser/content/browser.xul Line Number 53, Column 1:

<window id="main-window" ^ </p>

Tried starting Firefox with Shift, a smaller box(window) pops up with the same text for a fraction of a second and then disappears and Firefox shuts down.

Try to start firefox and a white screen pops up with: XML Parsing Error: undefined entity Location: chrome://browser/content/browser.xul Line Number 53, Column 1: <window id="main-window" ^ Tried starting Firefox with Shift, a smaller box(window) pops up with the same text for a fraction of a second and then disappears and Firefox shuts down.

Todas las respuestas (2)

FredMcD
FredMcD
more options

What's your computer system and Firefox version?

Let’s do a full clean re-install;

Download Firefox For All languages And Systems {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. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

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; https://support.mozilla.org/en-US/kb/install-firefox-linux

If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ 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.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia

Gunmetal
Gunmetal
more options

Having the same problem here, with a slight variance.

68.0 -> 68.0.1 upgrade triggered Win10 (1809) BSOD; now cannot load my profile. "XML Parsing Error: undefined entity" as above.

Exact output:

XML Parsing Error: undefined entity Location: chrome://browser/content/browser.xul Line Number 50, Column 1:<window id="main-window" ^ </p>

NOTE: this forum is munging my output, probably some kind of anti-XSS protection. Attaching an image which shows the exact output.

I have tried the steps suggested above, did not make any difference. Note that if I rename my Profile folder I can launch Firefox into a new profile. I just can't seem to access my original profile. I have a lot of data there (bookmarks, history, tabs, creds, etc.) so I'm really hoping I'm not permanently locked out of it....

Modificadas por Gunmetal el