Chosen Solution
This 15” MBP is my emergency laptop. But my main 13” MBP (containing all my ongoing files) was having some issues and needed repairing, so — since both laptops run OS High Sierra, and both use Samsung SSDs — I thought I could just take the SSD out of my 13”, put it in the backup 15”, and continue to work off the 15” until the 13” was fixed. It didn’t work: The 15” wouldn’t recognise the switched SSD (flashing question-mark folder). So I put the original SSDs back in their respective laptops … and now the 15” won’t switch back on. (It switched on initially, but then powered itself off at some point in the night, and then … nothing. Since then: No power, no light, no chime, no life at all. It’s just acting completely dead.) The battery was in good condition before this. I’ve obviously tried taking it out, reseating it, and putting it back in.The power cable light shows green. I have left it charging overnight for hours and in the morning … still no life from the laptopI have tried SMC resetI thought from similar posts (e.g., My Mac won’t turn on after I replaced Hard Drive AND Computer dead after hard drive replacement) that I might have damaged the SATA cable. But I’ve bought a new SATA cable and installed it and … nothing. Makes no difference It’s infuriating. It was fine, and all I did was try to use a different HD – didn’t work and put the original back in – and now the laptop is completely kaput. (And it looks like I’m not the only one having this sort of problem — e.g., After HDD Replacement, Won’t turn on) What could it be??
You’re hitting a few possible issues here: As you are running High Sierra with a SSD drive you have a risk of which file system the drive is using. So your newer 13” system’s SSD drive was likely setup with GUID/APFS, unlike your 15” 2008/09 which was setup with GUID/HFS+ So swapping the drives around won’t be possible as your older mac won’t boot up with the APFS as Apple didn’t update the older systems firmware to support boot up via APFS volumes. The second issue is your systems SATA port. Your newer 13” system likely has a SATA III (6.0 Gb/s) HD drive port unlike your 15” which is only SATA II (3.0 Gb/s) So depending on the given drive you can encounter issues! While you told us you have a Samsung SSD you didn’t tell us which ones. The older series are fixed I/O speed the newer ones are auto sense which allow it to work across the different SATA I/O’s SATA I, II or III your system offers. One of the confusing issues is with SATA compatibility! Let’s look at this like a car and a road. a Jeep Outback can drive on a rocky dirt road, whereas a Porsche 411 would get hung up on the rocks in the road. And yet the Jeep wouldn’t win the race on a race track where the Porsche wouldn’t even need to push its self that hard. So clearly having the right vehicle for the terrain is important! But there are vehicle’s which can do both! While they can’t do well in the extreme cases they are able to cross a stream on a dirt road or handle driving the kids around town. So with that how does this play with SATA interfaces and drives? The SATA standard group SATA-IO defined it that a slower I/O drive SATA I (1.5 Gb/s) can be used in a SATA II or SATA III based system, Likewise a SATA II (3.0 Gb/s) drive can work in a SATA III (6.0 Gb/s) System. But! A faster Fixed I/O speed drive won’t work properly in a slower I/O systems. So a fixed SATA III drive won’t work in a SATA I or II system. To add a bit of confusion! The drive makers wanted to make fewer drives and have a way to offer drives for these older systems, so they created a new class of drives Auto Sense! These drives have an added circuit to sense what the I/O speed of the system is, and then set the drive to that I/O speed. So you can find a SATA III drive that will play nice in a SATA I or II system! But you need to check the drives spec sheet to see if the I/O speed of your system is listed or not. While these where popular just a few years ago, HD makers are fighting the SSD makers prices so this feature is disappearing! Most HDD’s today no longer offer it as the market for SATA I or SATA II drives is mostly gone as these systems are slowly being tossed. Seagate (HDDs) & Samsung (SSD’s) still offer drives but they are being slowly being phased out.
