Hey. I need some answers to my following questions. Any help would be appreciated. Firstly, i am about to buy a second hand Mid-2012 Retina MacBook Pro 15" with 8GB RAM / 256GB SSD Here's my questions. 1) Until 2-3 days, i thought the Retina model MacBooks are not eligible for RAM or SSD upgrade or replacement. I simply thought they are just clued to the mainboard and there is no way to replace or upgrade them. This thought was come from what i read before but here is a simple guide link that i found to easily replace them. (Please tell me if links to other sites are not allowed) https://www.laptopmag.com/articles/upgrade-ssd-macbook-pro-retina-display So, if it's possible and that easy, what kind of ssd should i buy to be compatible with the rMBP ? 2) Will removing the old SSD from a rMBP, or any other computer , and replacing with a brand new SSD , delete all of previous files and any other data from the system (computer) or do i need any other things to do? My main purpose is, getting that second hand macbook and turn it into a brand new , factory-shipped macbook for my use. Let me be more spesific to my second question. Are SSD's the only mechanism that hold any data from previous user or can RAM or/and any other system piece hold any data too? Thank you.