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I get an error message when trying to open Firefox: load: TypeError: Components.classes['@checkpoint.com/XPCOMTrustCheckerMozilla/TrustCheckerMozilla;1'] is undefined, what can I do?

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  • Last reply by cor-el

This error message has a box with OK in it which I have to press to get Mozilla to open. It is also very slow for the message to come up but opens straight away when the ok button is pressed. Download speeds are very uneven and sometimes it takes a site 5 minutes to open.

This error message has a box with OK in it which I have to press to get Mozilla to open. It is also very slow for the message to come up but opens straight away when the ok button is pressed. Download speeds are very uneven and sometimes it takes a site 5 minutes to open.

All Replies (1)

This issue can be caused by an extension or plugin that isn't working properly.

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).

  • Don't make any changes on the Safe mode start window.

See:

If it does work in Safe-mode then disable all extensions and then try to find which is causing it by enabling one at a time until the problem reappears.

  • Use "Disable all add-ons" on the Safe mode start window to disable all extensions.
  • Close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")