Samsung 850 EVO in Early Macbook Pro

I'm having a very similar problem with a samsung 850 evo ssd inside a mid 2012 MacBook Pro running Yosemite public beta. (I understand it could be a beta problem haven't rolled back yet)

i was getting the odd crash and then dreaded white screen telling me I shutdown because of a problem. first time it happened I searched forums and reseated ram. This seemed to work for a short while then back again. It got more and more frequent until yesterday it crashed and then wouldn't boot up.

Went into to recovery mode to verify disk where it came up with an issue on the samsung. (I have two hard drives installed) so repaired disk and tried to do a time machine backup. This is when it started rebooting into recovery mode again after about an hour or so (different time every time). I tried removing the original hard drive (which was in the primary slot and moving the ssd from the dvd drive mod into the primary). Still the same problem. I haven't tried any of the suggestions here yet. But I'll let you know how I get on.

Your problem is potentially very different from the original poster's so you should start a new thread with a description of this problem. The use of a data doubler to replace the DVD with another drive may be complicit in your problem.

Hello, I just bought the same SSD and tried to format it using the internal cable, but it failed. I'm curious to see if you've solved your problem?

I read the reply where it says that it can't be done internally, so I'm going to get a SATA-USB cable tonight to try the external format.

If that doesn't work, I guess I'll have to replace the ribbon cable since I've had a similar problem with another brand new SSD which I ended up returning to the shop.

My issue was a bad SATA cable.

When I connected the SSD externally it worked perfectly. Ordered a new cable online and I was good to go.

Good luck!

My issue was also a bad SATA cable internally. My samsung 850 EVO 250GB worked fine externally thru SATA-USB cable.And I also got all possible errors when having the SSD inside the macbook, couldnt unmount, partition/erase and so on. So I finally went thru with the SATA cable switch. And then it worked!

Somehow I had the same problem but was able to fix it. My computer is a 2010 macbook pro running on Mavericks

After cloning my SSD, I installed my 250 gb 850 evo SSD into my macbook pro but it wasn't detecting. Thought the cable was damaged during installation so I reinstalled my old HDD and it worked. I installed my SSD into an external casing and was able to boot up the SSD externally. So I figured that my SSD must be working. I was considering buying a new SATA cable because the impression I got from reading all the forums was that my internal SATA cable was damaged.

I reinstalled the SSD, but this time I held 'option' and it detected my SSD as an internal drive!

My computer was exponentially faster on the internal SSD. For a couple of days, I was turning on my computer by pressing option. Eventually, I mucked around with my settings, went to system preferences, startup disk, clicked on my SSD, and now my computer turns on without holding option.

Hope this helps someone!

I just put in the ssd 850 evo 500gb to my early 2011 macbook pro. I was able to install it, then from disk utility, format and start restore from time machine (my old HDD died). Everything worked well so I decided to upgrade to Yosemite. That is when things went bad. Started to freeze occasionally at first that I could get out of by closing the program ,then progressively got worse until it froze where I couldn't get it going (all within a few hours). Had grey screen that wouldn't respond until I forced quit. I'm thinking the problem is with Trim. Because you can't have Trim and security both with Yosemite, I went back and was able with several tries to reformat the drive and reinstalled Mavericks then enabled Trim. It has worked fast and without problems so far. I thought the samsung 850 evo ssd had internal garbage collection with it, but must not work well in Yosemite.

i just recently installed this ssd in my late-2009 white unibody macbook. i'm only getting 250mb/s read and 200mb/s write speeds as opposed to the advertised 540 read and 520 write. just wondering what speeds you're getting and if there's anything I need to do to optimize performance.

The reason you're not getting the same speeds as the 2011+ macs is because your SSD is running over a SATA II connection instead of SATA III. SATA I is up to 150MB/s, SATA II is up to 300MB/s, and SATA IIIis up to 600MB/s.

So I came here looking for answers as my Macbook Pro 13 (2012) was having problems with exactly the same drive. I'm covered by Apple Care so I sent the computer in for repair. The Genius changed the sata cable and tried with a new drive and that worked perfectly. However, with my 850 EVO it was reporting issues with SMART and would not boot/format/reinstall properly.

I then went to look for SMART utilities to tell me the cause of the error and it appears that there are a huge number of CRC errors, a symptom that seems to point to either a busted cable, bad TRIM, bad SATA controller or a broken drive. The same SSD works perfectly on a Windows notebook so I was beginning to feel that it wasn't a problem with the drive itself.

My final conclusion was that with the old TRIM tool on OSx, it was incompatible with El Capitan and logged a lot of CRC errors on the SSD. This it turn triggered a SMART error which made OSx halt operations on the SSD. Windows seem to be a little more laxed on the SMART check and would continue to run fine on the same SSD that won't run on a Macbook. I'm going to exchange the SSD and see if a new one fixes this.

The same problem here. Mid 2012 Macbook pro recognizes Samsung EVO 850 but I can't format it (or erase it) - it gives me error:

"Unable to write to the last block of the device"

There is no firmware update for this SSD, the only thing I can try is to replace sata cable.

(My old hdd (original) died. So this might be solution)

Anyone else solved a problem with sata cable?

Replacing SATA cable worked for me. According to this guy (http://youtu.be/hnNA2Dyxe3s ) question mark and a folder means broken sata cable

Yesterday i replaced an ocz ssd of my macbook pro mid 2012 with a samsung evo 850 pro.

It boots fine. I' am actually writing on it but, i have some problems with writing speed. It starts at full write speed but at next test it fall at half. Please see both screenshots. Can someone explain it?

Hi, I know its been a while, but any chance you can tell me what TRIM enabler you used, I'm using an 850 EVO in a USB3 caddy for my iMac Late 2012 and I'm about to put an OCZ ARC100 into my mid 2009 Macbook Pro, both running Yosemite, not sure yet to upgrade to El Capitan.

Thanks in advance

Mark

are you any of you guys running two internal hard drives?

my problem was that the SSD was in the normal slot. I have modified my macbook with a second hard drive that sits in the old cd slot. if you are having problems formatting the SSD it needs to be in the old CD drive slot to be able to format it.