I have been trying to install Thunderbird using the /S command and others I have tried as well as trying to set the application to be the default mail program. here is my code: RunOnceEx.cmd REG ADD %KEY%\050 /VE /D "Mozilla ThunderBird 1.0" /f REG ADD %KEY%\050 /V 1 /D "%systemdrive%\Install\Thunderbird\Thunderbird.exe /S" /f REG ADD %KEY%\050 /V 2 /D "REGEDIT /S %systemdrive%\Install\Thunderbird\register.reg" /f register.reg Windows Registry Editor Version 5.00 [HKEY_CLASSES_ROOT\mailto\shell\open\command] @="C:\PROGRA~1\MOZILL~2\THUNDE~1.EXE -compose %1" [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\mailto\shell\open\command] @="C:\PROGRA~1\MOZILL~2\THUNDE~1.EXE -compose %1" for some reason I have all my programs being installed, but when I hit 050, Thunderbird doesnt install nor does the registry. What am I doing wrong, or what other options can I try to make this work? I have been searching the forums for 2 days and am using the install provided by Dave332 from here: Here's Thunderbird Unattended The site and forums so far have been a huge help, thank you.