I need to run Firefox each time in a new profile directory with my extension enabled. What I do is the following: Create temporary directory for storing profile (/tmp/profile.123) Create extensions directory (/tmp/profile.123/extensions) Create extension proxy as described here (/tmp/profile.123/extensions/[email protected]) My command line looks like this: firefox -no-remote -profile /tmp/profile.123 -url http://www.google.com The problem is that my extension starts disabled, and I'm forced to enable it manually and restart the Firefox. Is it possible to make it start enabled in first place? Thanks! Workaround I've found: Create extensions.sqlite database file in the newly created profile folder. This file must contain my extension entry under the "addon" table.