I have a mid-2014 15" Retina MBP and I want to upgrade the SSD from the current 512GB to a 1TB as I'm running out of space. I will have run Time Machine just before the upgrade process. I would like to wipe the current SSD to make it available to sell to try to recoup some of my cost, so the question is how best to do this. The way I see it, I can wipe it after doing the TM backup using disk utility...then removing it and putting in the replacement SSD. Or, I can get an enclosure and create an external drive and wipe it after I know the restore went as planned. Here is my dilemma...I will have two good TM backups (redundant, but safer), so not too concerned about the install going bad. So, rather than buy an enclosure for a one-time need, I'd prefer to wipe prior to removing the old SSD. This will obviously remove the OS, so, do you install a new OS onto the new SSD? Or how does the MBP recognize the new SSD when it would come without any OS installed? Should I download a copy of the OS onto a flash drive or some other external HD, or can this be done via an Internet connection? I'm just not clear on what happens the first time I boot up the MBP after installing the new SSD. It will obviously not have any OS on the SSD like would be the first time you booted up the newly purchased computer. So how does it get that first OS. I believe I would be offered an option to do a restore from the TM backup, but my preference would be to first do a standalone OS install and THEN, restore the data from the TM backup.