Thunderbird → Betterbird Migration Script (macOS)

Automate the migration of your Thunderbird profile to Betterbird on macOS, with a safety‑first approach:

• Backups your Thunderbird profile as a timestamped .zip file
• Copies the profile folder to Betterbird’s own profile location
• Preserves all accounts, local mail, filters, address books, passwords¹ and most add‑ons
• Dry‑run mode to preview every action before touching any files

¹ Passwords stored in Thunderbird’s password manager are migrated; if you used the macOS Keychain you may need to re‑enter them.

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Prerequisites

• Thunderbird already set up and used at least once (so a profile exists)
• Betterbird downloaded from www.betterbird.eu but not launched yet
• macOS 10.15 or later (the script relies on ~/Library paths)

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Quick Start

1. Quit Thunderbird and Betterbird completely.

2. Download and save the script as migrate.sh.

3. Make it executable:

   chmod +x migrate.sh
   

4. Do a dry‑run (highly recommended):

   ./migrate.sh --dry-run
   

   This shows every folder that will be created, every file that will be copied, and any potential conflicts – without actually changing anything.

5. Run the real migration:

   ./migrate.sh
   

6. Launch Betterbird with the Profile Manager:

   • Option 1: Hold the Option (⌥) key while double‑clicking the Betterbird icon.

   • Option 2: From Terminal:

     /Applications/Betterbird.app/Contents/MacOS/betterbird -profilemanager
     

   • Choose Create Profile… → Next → Choose Folder… and select the folder that was copied (it will be inside ~/Library/Application Support/Betterbird/Profiles/).

   • Start Betterbird with that profile.

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What the script does

1. Finds your active Thunderbird profile (using profiles.ini).
   If it can’t determine the default, it copies all profiles.

2. Creates a zip backup on your Desktop (~/Desktop/Thunderbird_Backups/).

3. Copies the profile folder(s) to ~/Library/Application Support/Betterbird/Profiles/.

4. Skips copying if a Betterbird profile with the same name already exists (to avoid accidental overwrites).

Your original Thunderbird profile remains completely untouched.

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Options

Flag	Description
--dry-run or -n	Prints every command that would be executed without actually running them.

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Restoring from backup

If something goes wrong:

1. Quit Betterbird.
2. Remove the faulty Betterbird profile folder from ~/Library/Application Support/Betterbird/Profiles/.
3. Unzip your backup (found on your Desktop) into that same location.
4. Re‑point Betterbird’s Profile Manager to the restored folder.

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Troubleshooting

“no such file or directory: /Applications/Betterbird.app/Contents/MacOS/betterbird”

Betterbird is either not installed or is in a different location.

• Check with ls /Applications | grep -i betterbird.
• If installed as “Betterbird Beta.app”, adjust the path accordingly, or simply hold ⌥ Option while opening the app to force the Profile Manager.

The script can’t find my Thunderbird profile

Ensure Thunderbird has been launched at least once on your Mac.
Manually locate your profile at:
~/Library/Thunderbird/Profiles/

After migration Betterbird asks for passwords

This is normal if you stored passwords in the macOS Keychain. Re‑enter them; they will be saved inside Betterbird’s own password manager.

Some add‑ons didn’t transfer

Most Thunderbird add‑ons work perfectly. If one doesn’t, reinstall it from addons.thunderbird.net – Betterbird is fully compatible.

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License

This script is provided as‑is, free to use and modify. No warranty – always keep a backup of your data.