Just to share my method, this is what i use for Firefox 2.0 silent installation For firefox i use "Firefox2.exe -ms" then the flash player "install_flash_player.exe /s" and shockwave using the switchless pack "swinstaller1.exe" finally a batch file "FF_ext_installer.bat" ---FF_ext_installer.bat------- (all *.xpi extension must be same within same folder) @echo off REM INSTALLING FIREFOX EXTENSIONS. for %%e in ("*.xpi") do "C:\Program Files\Mozilla Firefox\Firefox.exe" -install-global-extension "%%e" exit --------------------------------- With this method it will whatever *.XPI in the same folder.