you remind me something - plugin-container can be disabled in firefox itself - ofc its a firefox program, not from windows. plugin-container was developed to avoid firefox crashes when plugin (any) crashes (similar to chrome instance with flash). concerning firewall - short test - you are right - although plugin-container wants internet access some times and only flash is running on that sites. strange. (protectedmode=0 in mms.cfg) anyway - flash is working inside sandboxie. i wont argue against you if it wont be. in front of users computer i would have the chance to determine the troublemaker.