{nav icon=home, name=Main Page > icon=wrench, name=Troubleshooting > Firefox Compatibility Mode} Enable Firefox Compatibility Mode to install add-ons from [Mozilla add-ons website](https://addons.mozilla.org) --- Open `PureBrowser` and type **//about:config//** into location bar and hit Enter, a warning will popup: {F32076, size=full, alt=ff1} Click !!I'l be careful, I promise!!! button, and type **//useragent.compat//** into the search bar, then double-click the preference to change its value to `true`: {F32078, size=full, alt=ff2} In recent versions of PureBrowser this is already set to `true` so you don't have to change it. You will also have to change your [useragent string](https://en.wikipedia.org/wiki/User_agent#Format_for_human-operated_web_browsers) to install Firefox addons. To do this, open **//about:config//**, right-click, select //New// -> //String// , enter `general.useragent.override`, and enter `Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/68.0.2` as a string value. Then, click "Okay" and reload the page.