Start Mozilla Thunderbird in Safe Mode

The Mozilla Thunderbird logo.


Is Mozilla Thunderbird refusing to start and showing a cryptic error message—or nothing at all?

Don't panic, at least not yet. Chances are a troublesome extension is wreaking havoc. Get rid of the extension and you rid Mozilla Thunderbird of its problems.

How, though, can one uninstall an ​add-on without the menus and dialogs in Mozilla Thunderbird that make that possible? Fortunately, Mozilla Thunderbird includes a "safe" mode that disables all extensions before (hopefully) launching the application. You can then uninstall problematic extensions.

Start Mozilla Thunderbird in Safe Mode to Uninstall Broken Extensions

To launch Mozilla Thunderbird in Safe Mode and get rid of extensions that cause problems, first make sure Mozilla Thunderbird is not running. Then, follow the instructions below for your operating system.

For Windows Users

  • Select Mozilla Thunderbird (Safe Mode) from Start | All Programs | Mozilla Thunderbird.
  • If you do not have that entry in your Start menu:
  • Press Windows-R.
  • Type thunderbird -safe-mode
  • Click OK.

For Mac OS X Users

  • Launch Terminal (type terminal in Spotlight search and click Terminal under Applications in the search results).
  • Type thunderbird in the Spotlight menu bar search field.
  • Click Show All.
  • Drag and drop Thunderbird from the Applications category to the Terminal window.
  • Append Contents/­MacOS/­thunderbird-bin -safe-mode to
  • Make sure you delete the white space character at the end of before completing the command line.
  • If Mozilla Thunderbird is installed in the default applications directory, the command line will be /Applications/­­Contents/­MacOS/­thunderbird-bin -safe-mode
  • Press Enter.

For Linux Users

  • Type [path to Mozilla Thunderbird]/thunderbird -safe-mode at a command line.
  • You can find the full path to Mozilla Thunderbird by typing which thunderbird at a command prompt followed by Enter.
  • Press Enter.
  • Select Tools | Add-ons from the menu in Mozilla Thunderbird.
  • Go to the Extensions category.
  • Highlight the troubling extension.
  • Click Uninstall.
  • Click Uninstall again.
  • Shut down Mozilla Thunderbird.
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