Chosen Solution

Hi All, Just as a forward, I have been all over reddit and ifixit looking at many similar questions but with slight variations and none of those fixes have worked for me. I recently endeavoured to take this old MacBook Pro 13 (2012) and breathe new life into it with a new battery & SSD. Battery and SSD physical installation went fine. Unfortunately, from the very start I have had many problems with the software and experience of the SSD. First, it was nearly impossible to get MacOS onto the SSD as the download and install process would take hours and inevitably crash; after many days and failed attempts I finally got a High Sierra installation successfully into it, but when booting up and even after logging in, the performance was extremely, extremely laggy; slower than AOL dial-up laggy. I tried an NVRAM and SMC reset, no change. I have been virtually unable to even find let alone install a firmware update for the device as Samsung’s website only seems to have updates available for the 850 EVO (mine’s an 860). I have heard conflicting reports about the problem perhaps being the internal SATA cable connector. My technically-oriented friends say that’s highly unlikely, and indeed it works fine still with the base HDD. However, when I have the SSD hooked up through an external SATA-USB housing, it runs smooth as butter. So, could that really be it? Would I need a specific kind of SATA cable for it to make a difference? (there doesn’t seem to be anything obviously wrong with my current one) I am wondering if it’s not it, if there are other optimisations I need to make between the rest of my MacBook’s hardware and this new, alien SSD I am introducing. Please help, I’m going crazy after weeks of trying different things, and would like to save myself €50 on the SATA cable that the iFixit guide recommends since it doesn’t seem any different from the OEM one I have… Cheers, Desperate Newb

@playerofmemes - Sorry to say you do have a bad cable here. Let’s use an analog to see what’s happening here. Here in Boston we get major traffic jams in the morning rush when one of the major highways gets an accident. Some cars & trucks can sneak through but others get blocked until they can get around the blockage. Now if this happened in the early morning before the traffic built up the few cars & trucks on the highway have no real problem getting by. So how does this apply to my problem?? This gets into more than the SATA I/O speed of your system which is SATA III (6.0 Gb/s) in this case your original Apple drive might be only a SATA II (3.0 Gb/s) drive and to add to this its only a 5200 RPM drive. So the amount the data flow at max is not pushing the ability of the SATA port on your logic board. So if you have a fatigue cable or one which is only rated for SATA II you won’t encounter any issues at all! (Think of the 2AM traffic flow). Now you’ve put in a very efficient SATA drive which can push the limits of the SATA III (6.0 Gb/s) channel. Now think how much data could flow across that weak or under rated cable! OK, so I need a new cable! Here’s the correct cable you’ll need MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable and here’s the guide MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement. But even this is not enough! You need to also need to place a strip of electricians tape on the uppercase where the cable crosses over to help protect it from the rough aluminum surface. Then the way you fold the cable is important! A common issue I see is people over do the folding which fatigues the thin foil wires. Here we need a arch not a sharp fold. To help here I use a BIC pen ink straw to help me roll the cable into a nice radius curve that way I don’t damage the wires. Now the last part once you replace the cable you’ll want to backup your drive as you’ll need to reformat it and do a fresh install again as you may have some corrupted blocks that need to be reset.

A few questions, when installing MacOS High Sierra (HS) or higher. Was the drive formatted as Mac OS Journaled / GUID Partition Table before installing? Don’t think it’s a SATA cable problem because it works fine on hard drive. Since HS is installed, do an update to Mojave while booted into MacOS via App store to ensure the firmware ( SMC / BIOS ) on the board is updated to a newer version.

I had the same problem. Suddenly the laptop started to malfunction and the spinning wheel kept turning even when I was trying to enter the password. I put the old hard drive in and it was working, slower of course but fine. While the old hard drive was working properly, with the SSD I could not for any reason install the new operating system. It took many hours for this, and then it failed. I got the laptop and went to an authorized repairer right away and the problem was what I was thinking about. The hard disk cable was damaged although not visible. They changed it and now it’s fine. They told me that many macbook’s had the same problem.