Chosen Solution

I picked up a MacBook Pro A1398 for fairly cheap and it did not include an SSD. Does apple use a proprietary SSD or can I put another type of SSD in there?

Apple always use proprietary SSDs on Retina MacBook Pros, however it is just in form factor. I believe in some models it is possible to make it work with an adaptor, but you wouldn’t be able to close the bottom lid because there won’t be enough space.

I just completed this upgrade using a regular SSD and an adaptor for my mid 2012 retina macbook pro. You have two options:

  1. Buy an m2 form factor SSD from OWC or from ifixit
  2. Buy a regular ssd and buy a msata to M.2 adaptor - here are the ones I used: SAMSUNG 850 EVO mSATA 1TB Mini-SATA (mSATA) Internal SSD Single Unit Version MZ-M5E1T0BW mSATA SSD Adapter for MacBook Pro Retina A1425 MD212 MD213 ME662 (52 Pin) mSATA to USB 3 adaptor and M.2 to USB3 adaptor Then
  3. Backup your data to an external drive or two
  4. Confirm your backup works
  5. Put the mSATA SSD into the USB 3 adaptor
  6. Clone the internal SSD into the mSata SSD (use internet booting on your MBP or the backup from step #1
  7. Follow the iFixit tear down guide to extract the SSD and install the mSATA SSD (that you have put into the MSATA SSD to M.2 Adaptor