I keep getting a lot of asks or seeing comments about it, even though it is explained in the FAQ, so I’m just gonna post this here and on the News section, just in case.

This might happen if you delete your cookies and stored application data. If you are using “Clear Browsing Data” or any other similar feature, this might also delete XKit data.

If you want to delete data stored on your computer, do not choose “Delete cookies and other site and plug-in data”, “Clear data from hosted apps”, “Delete Offline Website Data” or any other setting. Doing so will cause your browser to delete XKit’s data, prompting it to re-install itself.

There is nothing I can do about this, you are ordering your browser to clean XKit data. I can’t make XKit say “okay delete all user data but leave me alone” to your browser.