Hi, I'm guessing you tried to restore hundreds or even thousands of tabs all at once. In the upcoming version (v2.4+, coming in the next few weeks) there is new option to restore tabs in an "unloaded" state, so that Firefox does not try to load each web page. For others that are confused: it's not OneTab that is hogging all of your RAM, it's the huge number of pages you decided to restore all at once that is causing this issue.