I was receiving the "No recently used apps" message. Reboot fixed for an indeterminate amount of time. Then I noticed anytime I used Google Now is when the recent apps stop displaying apps and just give me that message. So I decided it might have something to do with that. I went under the Application Manager and found the "Google App". Forced Stopped. Clicked on Storage, then cleared cache. Then opened up my recent apps and they all were there! Then I went back and tried to use the Google Now. It sent me through the setup process again, but Recent Apps has been working like its supposed to be ever since. 3 or 4 days straight no problems with recent apps even after I used Google Now. Maybe this will help someone.