Starting Thunderbird with no Extensions

Extensions are wonderful things. (What are extensions?) But sometimes they don't play nicely with each other, and it's hard to determine where the problem is.

The first thing you should try is running Thunderbird with no extensions, to see if that clears up the problem.

On Windows computers, you'll find a Mozilla Thunderbird (No Extensions) item in the Mozilla Thunderbird folder in your Start Menu.

On Macintosh computers, well, sorry, but Mozilla hasn't built-in an easy way, so here's what you do.

1. In the Finder, choose the Applications folder, then the Utility folder.
2. Run Terminal. A small Terminal window will open.
3. Type in the following, then press Enter

/Applications/Thunderbird.app/Contents/MacOS/thunderbird-bin -safe-mode

You must type it exactly like this, with the slashes and the uppercase letters where shown. Please note that after the last slash, there is only one space:

thunderbirddashbinspacedashsafedashmode

4. Thunderbird will open with no extensions.