MacBook Pro ejecting secondary internal drive

I just got a mid-2012 MBP 15" non-retina to replace a dead 2011 17". Long story... My 17" had an SSD in the HD slot and a 2T HD in the optical bay. I moved them over to the 2012 and they mostly worked. After some work I got the SSD working well but the HD would disconnect after a few minutes. That's why I found this thread. I read through the thread and it reminded me of the problem I had with the SSD in my 17": it would disconnect in the same way. the issue was the cable was not shielded enough for whatever protocol was running on it with the SSD. To fix it I shielded it in copper tape and grounded the tape.

After messing around the HD in the 2015 trying to get it to work I ran into many of the things cited here: drive won't boot off the optical buss, etc. I decided to try first upgrading the OS. the SSD had El Capitain on it. So did a clean install of Sierra and a restore off my Time Machine. That really helped keep the HD up and running. it didn't seem to be disconnecting. However, I couldn't really move data to and from it quickly. I could download off the net to it but not copy to the SSD - the copy would terminiate with an error after some 10'sMs copied. So i wrapped the area where the drive connector meets the adaptors and the adaptors and the top of the flatflex going to the computer. I ensured it was all connected by soldering the pieces that made up the shield together, and tightening a section of it down under a screw to the metal chassis of the drive adator. the adaptor is also bolted to the case so there is a good ground here.

After booting it up, it worked great. I copied a 2G folder in less than a minute to the SSD! no problems. I was also having issues playing audio and video off it but now that was fixed.

So I am thinking the problem is that some HDs and SSD require more bandwidth or some other protocol on the cable that is not designed for it. Shielding it seems to help! I use a single sided copper tape I got off ebay. You have to be careful not to short anything with the copper side because it's bare copper.

Good luck.

Just an update. My inital attempt to shield the internal drive failed ultimately although it did stay active for a lot longer than before. I didn't completely shield the drive and cable. I shielded the top part of the drive, the area of the connectors. Since this helped, this time around I shielded everythign including both sides of the cable to the motherboard and also around the motherboard where the cable connects. This works better. Its only been about 30 minutes since I did this but I did copy a 7G movie to the drive while playing another movie off the drive and all went well. as well as deleting about 750,000 files over about 200G. so far so good. I will report back if this fails. If you don't hear from me, it worked.

The drive is the venerable Samsung Momentus Spinpoint M9T ST2000LM003 2T 2.5"

UPDATE: No go. I have completely shielded the drive, adaptor and cable and even the area around the motherboard where the cable connects. This did help even more with the drive but eventually it would disconnect. It seems to me that the SATA buss for the optical drive has some kind of issue where even though its speced for 6Gb/s, it can't handle it. There are other posts out there documenting this and this would be why no amount of shielding will help - its a design flaw.

I have reverted to the 750G 3Gb/s drive from my 2011 machine and that has been working fine. I think if you get a drive in there that only works at up to 3Gb/s then it should work ok. I am currently trying to find the largest 3Gb/s drive I can find but it's tricky.

Some more info: I looked into what appears to be the only solution for this which is an adaptor/caddy made by another company. I emailed with them and they guarantee that it will work with things like the 2T drive I couldn't get working. I asked if it was an active solution (meaning powered) and they said it was not a pass-through device (so it is active). I asked if it somehow processed the data stream somehow to be compatible with the SATA buss on the motherboard. They said no, that it cleans up the signal. So, knowing a bit about electronics, I looked into this. Turns out there are some devices out there that are designed to "redrive" SATA - that is, clean up the signal, boost it if needed and clean up the leading/trailing edges of the data signal. I figure this is what the product is using.

I wonder if this is the solution to this problem: wire in a SATA "re-driver" into the interface between the drive and motherboard. Of course you need to have electronics experience to do this (which I have). The parts would cost about $30CAD (chip and break-out board). It makes me wonder if this is the issue - that the signal off the drive is such that however Apple implemented SATA on the optical buss, the signal is not of sufficient quality to be reliable. Since they are using off-the-shelf parts for these interfaces on the motherboard (I think) it means that perhaps it is the cable to the motherboard that is the problem? Perhaps that cable is not designed to preserve the SATA signal to the degree required to be 6Gb/s compliant and this is why it needs to be "re-driven".

In any case the part that looks like it might work is a TI SN75LVCP601 Two channel SATA 6Gb/s Redriver. That, a breakout board, and some soldering and it might work. The tricky part would be getting the SATA connectors connected in a way that is compliant. I don't know about SATA from an electrical characteristics perspective so I dont know if a simple twisted-pair would work or not.

In any case, my speculation is that the 6Gb/s signal is not implemented properly on the motherboard and requires being cleaned up by something like the SN75LVCP601.

It appears you can buy this active caddy interface product and it will work. Or, try and hack your own redriver into your mac. Maybe one day I will try it!

I doubt the person that wrote the above styatement has any idea what he is talking about. There are many people running the same, or very similar, configuration as you and they don't have this problem.

Do you get a warning like "drive 2 was ejected improperly"? Or does the drive just drop off?

Could be the power saving features. Try unchecking "Put HDD to sleep whenever possible (or something like that).

Personally I think it is the cable going to the second drive.

The optibay 2nd HD is a good idea. In theory only 😐

7200rpm HD and the 2 platter 1TB might be too much power for consistent use thru the SATA feed meant for the superdrive you replaced it with, however that is indeterminate .

I bet if you used a conventional 1tb 5400rpm it would work.,....and KNOW it would work with a 1 platter 5400 500gig. Countless 1000s are using such HD in the optibay.

Youve already swapped out SATA cables, which are very poor quality and was likely the cause of the issue, but now that that is disproved, all thats left is the spindle speed/ power on the 7200 2platter 1TB HD.

An unlikely source of being able to read for a min or so but not consistent as you report would be a power fault at the logic, which is very unlikely.

No, youd want in all instances your superfast SSD in your primary boot HD bay

You want that fast boot SSD in your primary bay and the slower conventional HD in your optibay.

Having the SSD in the optibay would be like sticking the race car driver in the back seat and putting granny at the wheel.

I have been using the Optibay for many years now with a 500G std drive. I have had this issue since the begining, but not that often. Had noticed that this would nearly systematically occure when I was using Adobe SW (i.e. Photoshop, etc) and Final Cut Pro. Not sure if there is any relation.. in any case, I'm here now because the issue is becoming more recurent than ever before (Maveriks?).... DJT.