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Mozilla Thunderbird

Version documented: 115.8.0 Installer type: .exe (NSIS) Hives written: HKCU, HKLM, HKCR

📁 Registry Paths

Path Hive Purpose
SOFTWARE\Mozilla\Mozilla Thunderbird HKLM Installation info
SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Mozilla Thunderbird HKLM Uninstall entry
SOFTWARE\Clients\Mail\Mozilla Thunderbird HKLM Default mail client registration
HKCR\mailto HKCR mailto: URI handler
HKCR\ThunderbirdEML HKCR .eml file type
HKCR\.eml HKCR .eml file association

🔑 Keys

HKLM\SOFTWARE\Mozilla\Mozilla Thunderbird

Value Name Type Example Data Description
CurrentVersion REG_SZ 115.8.0 (x64 en-US) Full version string

HKLM\SOFTWARE\Mozilla\Mozilla Thunderbird\115.8.0 (x64 en-US)\Main

Value Name Type Example Data Description
Install Directory REG_SZ C:\Program Files\Mozilla Thunderbird Install path
PathToExe REG_SZ C:\Program Files\Mozilla Thunderbird\thunderbird.exe Full exe path

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Mozilla Thunderbird

Value Name Type Example Data Description
DisplayName REG_SZ Mozilla Thunderbird 115.8.0 (x64 en-US) Display name
DisplayVersion REG_SZ 115.8.0 Version
Publisher REG_SZ Mozilla Publisher
InstallLocation REG_SZ C:\Program Files\Mozilla Thunderbird Install path
UninstallString REG_SZ "...\helper.exe" /uninstall Uninstaller

HKLM\SOFTWARE\Clients\Mail\Mozilla Thunderbird

Value Name Type Example Data Description
(Default) REG_SZ Mozilla Thunderbird Display name for default mail
DLLPath REG_SZ C:\Program Files\Mozilla Thunderbird\mozMapi32.dll MAPI DLL path

HKCR\mailto

Value Name Type Example Data Description
(Default) REG_SZ URL:MailTo Protocol Protocol description
URL Protocol REG_SZ `` Marks as URL handler
shell\open\command (Default) REG_SZ "thunderbird.exe" -osint -compose "%1" Open command

📝 Notes

  • Setting Thunderbird as default mail client writes the mailto: handler to both HKCU and HKLM.
  • Mail profiles, accounts, and messages are stored in %APPDATA%\Thunderbird\Profiles\ — back up this folder to migrate.
  • The MAPI DLL (mozMapi32.dll) enables "Send to mail" from other Windows applications.
# Check if Thunderbird is the default mail client
(Get-ItemProperty "HKLM:\SOFTWARE\Clients\Mail" -ErrorAction SilentlyContinue).'(Default)'

# Get install path
$ver = (Get-ItemProperty "HKLM:\SOFTWARE\Mozilla\Mozilla Thunderbird").CurrentVersion
(Get-ItemProperty "HKLM:\SOFTWARE\Mozilla\Mozilla Thunderbird\$ver\Main").'Install Directory'

🗑️ Cleanup

# Remove Thunderbird installation keys
Remove-Item -Path "HKLM:\SOFTWARE\Mozilla\Mozilla Thunderbird" -Recurse -ErrorAction SilentlyContinue
Remove-Item -Path "HKCR:\ThunderbirdEML" -Recurse -ErrorAction SilentlyContinue

# Remove mailto handler if Thunderbird owned it
$mapiDll = (Get-ItemProperty "HKCU:\SOFTWARE\Clients\Mail\Mozilla Thunderbird" -ErrorAction SilentlyContinue).DLLPath
if ($mapiDll -like "*Thunderbird*") {
    Remove-Item -Path "HKCU:\SOFTWARE\Clients\Mail\Mozilla Thunderbird" -Recurse -ErrorAction SilentlyContinue
}

📦 Package Managers

Manager ID / Command
winget winget install Mozilla.Thunderbird
Chocolatey choco install thunderbird
Scoop scoop install extras/thunderbird