How to uninstall Thunderbird on Mac

Thunderbird keeps your messages, address books, saved passwords and settings in a profile under ~/Library/Thunderbird, separate from the app. That is why you can remove and reinstall Thunderbird without losing mail, and also why the profile is the one thing to back up first. Mozilla's help is blunt that none of these count as a backup: mail on the server, the profile on this Mac, or a copy of it in cloud storage. Mail in Local Folders, and mail you downloaded with POP, can exist only in this profile. These steps cover Thunderbird downloaded from thunderbird.net and the Homebrew cask thunderbird; the recorded test used the download from thunderbird.net.

Back up the profile

  1. In Thunderbird, click ≡ › Help › Troubleshooting Information. Under Application Basics, find the Profile Folder row and click Show in Finder.
  2. If Thunderbird will not open, use Finder instead: open the Go menu, hold the Option key, choose Library, then open Thunderbird › Profiles.
  3. Quit Thunderbird. Copy the whole profile folder (its name ends in default-release unless you changed it) to another disk or folder outside Library.

Mozilla's help also offers Thunderbird's own export tool, and describes restoring by copying the folder back or importing it. Mozilla help: Thunderbird profiles

Do not keep the live profile in a synced cloud folder as your backup; Mozilla says running it from shared or cloud storage risks corrupting it, and that a profile in cloud storage is not a backup either.

Quit Thunderbird and remove the app

Quit Thunderbird with Command-Q, then move Thunderbird from Applications to the Trash. The profile stays on disk until you remove it yourself.

Where Thunderbird keeps its data

These are the paths in the Homebrew cask's zap list. Open each with Shift + Command + G in Finder; skip the ones that do not exist.

Location What it holds What to do
~/Library/Thunderbird profiles.ini and the Profiles folder: messages, address books, passwords, filters, settings Back up first; keep it unless you are sure the backup opens
~/Library/Application Support/Thunderbird Listed by the cask; it was empty on the test Mac Remove only after checking it is empty
~/Library/Caches/Thunderbird Disk cache Safe to remove after Thunderbird has quit
~/Library/Caches/Mozilla/updates/Applications/Thunderbird Downloaded Thunderbird updates Safe to remove
~/Library/Preferences/org.mozilla.thunderbird.plist App preferences Remove for a clean start
~/Library/Saved Application State/org.mozilla.thunderbird.savedState Window state Safe to remove

Leave ~/Library/Caches/Mozilla and ~/Library/Application Support/Mozilla themselves in place. Firefox and other Mozilla-based apps share those parent folders.

Check the result

Run these read-only commands in Terminal after the app is in the Trash:

pgrep -il thunderbird
ls "$HOME/Library/Thunderbird/Profiles"
  • No output from pgrep means Thunderbird has quit. A listed process means it is still running; quit it before copying or deleting the profile.
  • ls listing a folder such as xxxxxxxx.default-release means your mail is still on this Mac, which is what you want if you plan to reinstall. "No such file or directory" means the profile folder is gone; a folder named only default is usually an empty placeholder, according to Mozilla.

If you installed it with Homebrew

Running brew uninstall --cask --zap thunderbird yourself moves every path in the table above to the Trash, ~/Library/Thunderbird included, so your local mail goes with it. Back up first, or remove only the app:

brew uninstall --cask thunderbird

When Mole removes a Homebrew install, it checks the zap list first and leaves --zap out if it would reach a row you left unchecked. ~/Library/Thunderbird is unchecked by default, so a default removal keeps it and Mole moves only the rows you selected to the Trash. Homebrew Thunderbird cask

Accounts

Thunderbird has no account of its own. Removing it does not touch your mail accounts with their providers; IMAP mail stays on the server, but address books, filters and local folders stay only in the profile.

What Mole lists

For Thunderbird downloaded from thunderbird.net:

  • ~/Library/Thunderbird is listed but not selected.
  • ~/Library/Application Support/Thunderbird is listed but not selected.
  • ~/Library/Caches/Thunderbird, ~/Library/Caches/Mozilla/updates/Applications/Thunderbird, and the caches, preferences and saved window state filed under org.mozilla.thunderbird are selected by default.
  • ~/Library/Caches/Mozilla and ~/Library/Application Support/Mozilla are not listed.

What this test covered

Thunderbird was downloaded from thunderbird.net, copied into Applications and uninstalled with Mole Preview 277 on September 19, 2026. That build did not list ~/Library/Thunderbird, so the profile, about 15 MB, stayed on disk untouched; the empty ~/Library/Application Support/Thunderbird was labelled browser data and kept, because Thunderbird registers web links. The ~/Library/Thunderbird review row was added to Mole after this test. Backup and restore of a real mailbox and the Homebrew cask were not tested.