Here is the best and easy solution to make ThunderbirdPortable as Default Mail Client...
1. Create a subfolder in your ThunderbirdPortable folder (for example: "..\ThunderbirdPortable\Windows")
2. Change to the created subfolder to create the following batch-file...
3. Create a batch-file (for example: "Thunderbird Portable Integration.bat") with the following content :
@echo off Title Thunderbird Portable Integration & Color 1E cd /d %~dp0 ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :USERLOGON ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: for /f "tokens=2 delims=\" %%a in ('wmic computersystem get username') do set "USERLOGON=%%a" IF "%USERLOGON%" NEQ " " (set "USERLOGON=%USERNAME%") else (set "USERLOGON=%USERLOGON: =%") NET SESSION >NUL 2>&1 IF NOT %ERRORLEVEL% == 0 (SET "RUNAS=USER") ELSE (SET "RUNAS=ADMINISTRATOR") ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :CHECK ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: set "CURRENT-PATH=%CD%" & cd.. set "PROGRAM-PATH=%CD%" & cd %CURRENT-PATH% if exist "%PROGRAM-PATH%\ThunderbirdPortable.exe" goto :SETTINGS if exist "%CURRENT-PATH%\ThunderbirdPortable.exe" set PROGRAM-PATH=%CURRENT-PATH% & goto :SETTINGS ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :SETTINGS ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: set "PROGRAM-LINK=%CURRENT-PATH%\Thunderbird Portable.lnk" set "SENDTO-FILE=%CURRENT-PATH%\Thunderbird SendTo.cmd" set "SENDTO-ICON=%PROGRAM-PATH%\app\appinfo\appicon.ico" set "CONFIG-FILE=%CURRENT-PATH%\Thunderbird Portable.ini" set "ROAMING-PATH=C:\Users\%USERLOGON%\AppData\Roaming" ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: : START ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: cls echo ======================================================================================================================== echo THUNDERBIRD PORTABLE INTEGRATION (RUNNING AS: %RUNAS%) echo ======================================================================================================================== echo. echo PROGRAM-PATH : "%PROGRAM-PATH%" echo CURRENT-PATH : "%CURRENT-PATH%" echo PROGRAM-LINK : "%PROGRAM-LINK%" echo SENDTO-FILE : "%SENDTO-FILE%" echo SENDTO-ICON : "%SENDTO-ICON%" echo CONFIG-FILE : "%CONFIG-FILE%" echo ROAMING-PATH : "%ROAMING-PATH%" echo. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: : CHOICE ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: CHOICE /C YN /N /M "DO YOU WANT TO CONTINUE (Y/N): " IF %ERRORLEVEL%==1 GOTO :PROCESSING IF %ERRORLEVEL%==2 EXIT ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: : PROCESSING ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: if not exist "%PROGRAM-PATH%\ThunderbirdPortable.exe" goto :ERROR cls echo ======================================================================================================================== echo THUNDERBIRD PORTABLE INTEGRATION PROCESS (RUNNING AS: %RUNAS%) echo ======================================================================================================================== echo. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo CREATING CONFIG-FILE... ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo [General]>"%CONFIG-FILE%" echo StartWithLastProfile=^1>>"%CONFIG-FILE%" echo(>>"%CONFIG-FILE%" echo [Profile0]>>"%CONFIG-FILE%" echo Name=Portable>>"%CONFIG-FILE%" echo IsRelative=^0>>"%CONFIG-FILE%" echo Path=%PROGRAM-PATH%\Data\profile>>"%CONFIG-FILE%" echo Default=^1>>"%CONFIG-FILE%" echo. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo CREATING SENDTO-FILE... ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo @echo off>"%SENDTO-FILE%" echo if %%1. == . exit>>"%SENDTO-FILE%" echo set PARAMS=file:///%%1>>"%SENDTO-FILE%" echo :loop>>"%SENDTO-FILE%" echo shift>>"%SENDTO-FILE%" echo if %%1. == . goto send>>"%SENDTO-FILE%" echo set PARAMS=%%PARAMS%%,file:///%%1>>"%SENDTO-FILE%" echo goto loop>>"%SENDTO-FILE%" echo :send>>"%SENDTO-FILE%" echo start "Thunderbird" "%PROGRAM-PATH%\ThunderbirdPortable.exe" -compose attachment='%%PARAMS%%'>>"%SENDTO-FILE%" echo. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo CREATING PROGRAM-LINK... ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: set SCRIPT="%TEMP%\%RANDOM%-%RANDOM%-%RANDOM%-%RANDOM%.vbs" echo Set oWS = WScript.CreateObject("WScript.Shell")>>%SCRIPT% echo sLinkFile = "%PROGRAM-LINK%">>%SCRIPT% echo Set oLink = oWS.CreateShortcut(sLinkFile)>>%SCRIPT% echo oLink.TargetPath = "%SENDTO-FILE%">>%SCRIPT% echo oLink.IconLocation = "%SENDTO-ICON%">>%SCRIPT% echo oLink.Save>>%SCRIPT% cscript /nologo %SCRIPT% del %SCRIPT% echo. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo CLEANING OLD SENDTO-LINK... ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: del /Q /F "%ROAMING-PATH%\Microsoft\Windows\SendTo\Thunderbird*.lnk" echo. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo COPYING CREATED FILES... ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo. if not exist "%ROAMING-PATH%\Thunderbird" md "%ROAMING-PATH%\Thunderbird" copy "%CONFIG-FILE%" "%ROAMING-PATH%\Thunderbird\profiles.ini" copy "%PROGRAM-LINK%" "%ROAMING-PATH%\Microsoft\Windows\SendTo" ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :FINISH ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo. echo ======================================================================================================================== echo FINISH - THE DEFAULT-MAIL-CLIENT MUST BE SET MANUALLY - FIRST IN THUNDERBIRD - THEN IN YOUR WINDOWS-DEFAULT-APPS ! echo ======================================================================================================================== echo. pause exit ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :ERROR ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: echo ======================================================================================================================== echo ERROR - MOVE THIS BATCH INTO YOUR THUNDERBIRD-PORTABLE FOLDER OR SUBFOLDER ! echo ======================================================================================================================== echo. pause
4. Run created batch-file !
5. Default-Mail-Client must be set manually !
6. First in ThunderbirdPortable (Options/Settings)
7. Then in your Windows-Settings (Default-Apps)
8. Enjoy it !