So… I have a mid-2012 Macbook Pro. I have had it for a few years, and the hard drive has been swapped for an SSD. However, the whole time i've had it, i've had this problem where I have to turn it on and off until the drive shows up. I also can't have it closed for more than 10 minutes, or it crashes. Nearly every time I boot it, it says it restarted because of a problem. The restart wait has ranged from 5 minutes to over an hour. Most of the time, when the drive does show up, but it gets halfway booted, then a circle with a line through it shows up. Once it is booted, it works fine, but it ***** to sit there for usually a half hour booting my Macbook up. Please help!