Released June 2012, Model A1278. Intel processor with Turbo Boost, Up to 512 MB DDR5 Video RAM

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Second HDD in optical bay not working properly


I have installed a second 1TB HDD in place of the superdrive but it is not working well.

File reads from that HDD, file transfers to and from that HDD all result in a beach ball. If I try to do big transfers the HDD vanishes from the system! I have to reboot to see the HDD again!

Searching online I found this -

I thought problem solved. The Apple site with the update also states its for mid 2012 macbook pros -

However whenever I try to install the update it states "This update is not for this system". I am not sure but I think this is because I have OSX El Capitan running, rather OSX Lion or Mountain Lion.

I have OSX ML on an external HDD. Should I use it to boot my laptop and then apply this update? Will putting back the drive with El Capitan after the update cause any issues?

Is there something else I can do or should I just get an Intel 320 600 GB SATA II SSD instead for the optibay?

Answered! View the answer I have this problem too

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Can you give us the make and model of your HD's (both the primary & secondary).


For now I would hold off buying anything until we can guide you here with what you have now.


The main HDD is APPLE HDD HTS545050A7E362 , its 500 GB.

The secondary HDD is HGST HTS721010A9E630 , 1TB Travelstar 7K1000.

I had bought a Samsung 850 EVO 250GB which I intend to use to replace the primary HDD. Using the SSD for the OS/apps and HDD for data.

I don't want to mess with the primary HDD much, keeping it as a backup bootable drive for use if the EVO ever conks off.


How was the new drive formatted? Have you run Disk Utilities from the main drive on the new one?


Yes. It's formatted to HFS+ journaled. I have two partitions, 250GB and 750GB


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2 Answers

Chosen Solution

Both of your HD's are SATA III (6.0 Gb/s) drives. If we review the systems specs MacBook Pro 13" 2.5 GHz i5" (Mid-2012) your systems HD SATA port is SATA III but your systems optical drive port could be only SATA II (3.0 Gb/s). Using this as a reference: OWC Data Doubler We can see OWC lists their carrier as workable with your system (SATA III).

So from what you have things should work. So that leaves us the more likely issue here is the HD's SATA cable is not up to spec. Which is a common problem in this MacBook Pro series, I would start there.

MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable - Apple Part: 923-0104

Follow this IFIXIT guide: MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement

MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable Image


MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable


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Thanks. The Macbook Pro is still in warranty. Is there some way I can show the cable is faulty and get it replaced under warranty?


Apple is well aware of these faulty cables, they just don't want to admit it without a class action law suit. I'd just take it in (have your hard drive data backed up). Tell them it's the cable and that the cable may have damaged your hard drive (which it does 50% of the time) and request they fix it. Consider putting it back into the original configuration to avoid possible refute for unauthorized alterations.


I was travelling so couldn't respond earlier.

Dan I am accepting your answer.

I have since replaced the superdrive and swapped the original SATA II HDD first with a SATA III HDD and now a SSD. The macbook pro has been working fine, for now, but if problems develop I know what to do.



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A very useful post - I thank all who have contributed. Gautam, just trying to clarify what worked. Was it swapping the secondary HDD in the optical bay (I assume traditional platter mechanism) with an SSD? I too get a lot of beach balling with my similar setup. I attribute this to the fact that the secondary drive in the optical is a mechanical HDD. Will replacing that with an SSD solve my issues?

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Gautam Thakur will be eternally grateful.
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