Problems with Samsung 850 EVO SSD

@Diego - Lets see if I can correct some misconceptions here.

First (your points 1 & 2) you are correct the desktop systems SATA cables had to meet a spec that allowed use across all SATA I/O speeds. The issue here is a bit different here as Apple (as well as other laptop makers) make their own cable to suit their needs (space limitations). Here Apple had a few designs and the older version of their custom cable would not support SATA III performance and even the newer cable is fragile! So you can damage it if you're not careful.

As to the other issue you raise in your first point: Yes! The systems chipset defines the systems SATA ports speed. But you missed the issue of compatibility! The drive also has a SATA speed and the two need to be interoperable. The EIA/SATA standards group designed SATA to allow people to use older SATA I drives in newer SATA II or III systems so their data could be migrated to a newer system. What they didn't expect at the time they created the standard was the cost of drives to get so low so quickly.

cont: So today its not a matter of migrating to a newer system, more often it's upgrading an older system with a new drive! This is were the ability of a given drive can be an issue. a Fixed SATA II or SATA III drive will not work reliably in a SATA I system. Likewise, a Fixed SATA III drive will not work reliably in a SATA II system.

But, before you jump on me here there are drives which have either a jumper (older SATA II & III drives) to put the drive in SATA I mode. Or, today have auto SATA speed sense technology so the drive matches up with the systems SATA port. Here we need to review the spec sheet to see if the systems SATA port speed is listed. As an example heres a drive which is fixed: Seagate HD spec sheet now compare the line: Interface to this drive which has SATA port auto sense: Seagate SSHD spec sheet.

cont: So the SSHD drive will play in any system unlike the HD which will only work in a SATA III system only.

Your point #2: Has no bearing here as what a laptop uses for cabling is very different than a desktop system.

As to point #3: You should do some research! 2.5" SATA based SSD's which is what we are talking about here not Apples custom M.2 type blade SSD. So keeping the focus on 2.5" SSD's Samsung 850 EVO is one of the faster drives. But you should also look as other factors in the drive besides speed. Yes, Crucial makes a nice drive, but their warranty is not as good as Samsung's.

To put this all into perspective, I'm a EE as well and when I was younger I was very involved in the IEEE, EIA & TIA standards groups (computer networking). Today I'm semi retired fixing systems. Some of my clients deal with large number of laptop systems for their field staff. One customer has over 600 MacBook Pro systems most today have Seagate SSHD drives and we are migrating many to Samsung SSD's.

@lola - Please read my comments to Diego. I would have responded to his concerns sooner if I had seen it.

There is nothing wrong using the Samsung SSD in your system. I'm sure you have a bad cable here, I've often replaced them.

Just to help you over your concerns. Here's your SSD's spec sheet: Samsung 850 EVO SSD spec sheet. The Samsung 850 Pro version is no different: Samsung 850 PRO SSD spec sheet. Both offer SATA port auto sense.

Yes, you can put a Samsung's SSD,i will work fine without problems, now i will reply @danj

the cable have their own code right? which model unibody i should replace to? or i just can purchase the same model that inside my macbook pro ?

I switched out the SATA cable and it's work like a charm! Problem solved!

Yep, you have a bad cable! This is a common issue as the rough surface of the uppercase wears the cable. I strongly recommend you place some electrical tape down under the cable. As you have a 15" model follow the instructions here: MacBook Pro 15" Unibody Mid 2012 Hard Drive/IR Sensor Cable Replacement And this is the part you want: MacBook Pro 15" Unibody (Mid 2012) Hard Drive Cable - Apple P/N 923-0084

Sorry mjones - This is a SATA III system, Apple used a SATA II drive. As to the cable, laptops are not like desktop's! They use custom cables which the hardware maker designs. In this case Apples cable was not up to the task at running full out SATA III which is one of two reasons it needed to be replaced. The second issue is this cable has had some reliablity issues due to wear.

If this was a desktop then the SATA cable which is a standard part wouldn't be different between a SATA II or SATA III system. So in that case you would be correct!

The last point about data rates between SATA II & SATA III and the given system is a bit tricky here. A SATA III system can support any SATA drive (I,II, or III) which is how the standard was written.

Now to confuse you!

- A fixed SATA III drive will not play nice in either a SATA I or SATA II system! As it can't shift down to the slower data rates the system is expecting.

Now the bump!

- As it turns out the HD makers saw this as a problem and created a special type of drive that had the ability to sense the systems data rate and match it! These auto sense drives list two or three SATA specs in the Interface line in their spec sheet. As an example review these two spec sheets:

Seagate 2.5" SSHD

Seagate 2.5" HD

Note the interface line, in the 2nd its Fixed and the 1st its Auto Sense

Please be sure of your facts!

I've pointed to hard data to support what I stated. I also sat on the standards group meetings when a lot of this was decided so I know first hand the reasoning.

Don't confuse desktops & laptops they are very different beasts! A desktop SATA cable won't fit or work in a laptop so don't bring that into this.

Lastly, here is this systems specs: MacBook Pro 13" 2.9 GHz i7" (Mid-2012) did you read the systems SATA spec? Its SATA III (6.0 Gb/s) not SATA II (3.0 Gb's). Apple used a SATA II drive in the early systems.

And besides, people have reported back the solution was the correct answer. Not just here alone, but many other posts with the same or similar problem.

I too am eternally grateful to Dan. I have a MacBook Pro (13-inch, Mid 2012) that suffered a hard-drive crash several months ago. I purchased and installed the Samsung 850 Evo SSD, but the folks at the Apple store were unable to load OS Sierra or OS Capitan. We finally got OS Yosemite to load but, within days, stuff started going wrong (couldn't open files, couldn't save downloads, couldn't find the printer) and I eventually lost my desktop! The OS just disintegrated before my eyes - never seen anything like it. I read about the hard drive cable issue on this post so I purchased and installed the MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable recommended by Dan - figuring I had nothing else to lose. What do you know? OS High Sierra loaded in a flash and it has been smooth sailing ever since. The Geniuses at the Apple Store were unaware of this problem, so I told them to be on the lookout for many more of these cases.

After researching information here, this week I installed a new hard drive cable on my MacBookPro 13'‘ mid 2012 (9,2, 2.9 GHz, Intel Core i7.) It is running very smoothly, and I am extremely grateful for the help. I spent a lot of time trouble shooting this beast until I ran across the hard drive cable suggestion. (I used electrical tape on it as recommended.)

This machine has been on the shelf for about a year, and now it is running Catalina, with only a limited menu of apps for the time being.

By way of background, the hard drive developed a rattle and failed in 2019, and I had a Samsung SSD (EVO 860 500 GB) installed. After that, the startup and operation were painfully slow, but the technician said they had done everything they could think of and could do no more. The battery had failed, also, and the new one would not hold a charge. A new charger did not help, either. I am operating it without a battery at this time.

I'm a rookie but having fun learning. Thanks.