this is the 2.6, 512gb 8 gb version. Boot goes to apple almost instantly, but then the rotating circle keeps going on for 2-5 mins. sometimes it doesnt even load. these are the things i have tried: pram / smc reset many times selected the ssd as my start up drive. taken everything off from login startup apps reinstalled from scratch. Not from an image. Did the apple hardware test- everything passed. Nothing plugged in I have no idea whats going on. I have tested the speed of the SSD once logged in and everything is ok. 450+ read/write speeds. Temps are fine. Fans are ok. No lagging once in. It really is driving me insane. Do you guys have any other suggestions?