Quick Summary

The following document quickly illustrates how to remove the experiments.json file if there's issues installing the experiment. Regenerating a new experiments.json file should be the first troubleshooting step taken if there's any issues. Once Firefox is re-opened and reads the experiments manifest, a new experiments.json will be generated in the same location.

Removing experiments.json

Note: The profile directory on your computer might differ depending on your username/environment but should be very similar to the following examples:

• Windows: C:\Users\<current user>\AppData\Roaming\Mozilla\Firefox\Profiles\nae12udp.default
• OSX: /Users/<current user>/Library/Application Support/Firefox/Profiles/y35f3ueg.default
• Ubuntu: /home/<current user>/.mozilla/firefox/ezbdnu88.default/

Once you've deleted the current experiments.json file, re-run the browser and disable/enable experiments.enable under about:config.

You could also use the following commands inside the browser console to force a refresh:

• Import Experiments.jsm into the browser console:
  • Cu.import("resource:///modules/experiments/Experiments.jsm");
• Force the refresh inside the browser console:
  • Experiments.instance().updateManifest();

You should see some logs being dumped into the browser console and experiments.activeExperiment should appear as true if the experiment was installed.