Final Cut support

I rendered all my footage to an external hardrive, and a few days later I opened final cut back up without the hardrive plugged in, and all the rendering was gone. I plugged the hardrive back in and when I try to re-connect render files it would not let me click on "render" in the reconnect media window, only "online" and "offline" any ideas on how to get my render files connected with my footage in final cut?