firefox.exe -p -new-instance Should open a new instance of Firefox in the profile dialog, where you can create a new profile. I'm not sure about "-new-instanc

firefox.exe -p -new-instance Should open a new instance of Firefox in the profile dialog, where you can create a new profile. I'm not sure about "-new-instance". I've only used -no-remote but the release notes say remote commands have been removed. Some quick research turned up -new-instance as a substitute.