I'm trying to pre-setup a new Firefox installation with a custom user.js. However, no profile is made until Firefox is first run, unless you run this command:
Firefox.exe -CreateProfile <NAME>
Problem is, even if this command is run, Firefox will still create and launch with the default-release profile. Is there any way to set a default profile via the command line or by modifying a file?
Used Process Monitor to see what it does when changing default profile.
In %APPDATA%\Mozilla\Firefox\profiles.ini there's a Default=<Profile Path> line. Replace
<Profile Path> with your desired profile's path, which should be included in that file as well.
Ex.
Profiles/bd3a3mdf.default-release