Is it OK to replace the optical drive with a hard drive or SSD on Macbook Pro 13-inch mid 2012 (non-retina)? I heard it's buggy.

I have already replaced the hard drive with an SSD and it's now much faster. I'm thinking of replacing the optical drive with a Hard drive or SSD and use it for secondary storage with a Kit you can get out there. However, I heard it's not a very reliable fix and disconnects all the time or something like that? Anyone could please give me any hints on this?

  • Where have you heard it's unreliable or buggy?
    – Allan
    Commented Aug 18, 2018 at 10:26

4 Answers 4


I have heard of certain WD drives having hardware aggressive power saving features where the drive will shut down after a rather short period of inactivity. Worse, it doesn't tell the OS that it's doing so, so you get into a 'wait race' where the drive is waiting to be told to spin up, and the controller is waiting for the drive to signal 'ready'.

This usually isn't a problem if the computer shuts down the drive to save power: It then knows that the drive isn't ready, and sends the appropriate startup.

Try asking with more detail: Drive, kit, etc.

  • Hi, thanks for your answer. I was thinking of OWC Data Doubler but I guess others will give similar result. What you said happens only in the optical drive SATA port? Commented Aug 19, 2018 at 1:22

I have done this on that model of MBP. You need a purpose-built 'caddy', which is designed to house the SSD and to be the same shape as the removed optical drive. (And to stop you poking things through the drive slot.) OWC sells one called 'Data Doubler'.

I had no issues whatsoever, and the Crucial SSD I used performed well. There is a problem with the SATA connection cables on these models becoming unreliable, which can cause data slow-downs or possible disconnections. That might be what you've heard. However, replacements for these internal cables are very cheap.

The other 'issue' is the task of disassembly to get the optical drive out and the new caddy in. If you do not reconnect the various little connectors (or if you break them), then obviously that will affect things. However, carefully following one of the many strip-down videos, such as on ifixit.com, should see you through.


I have seen a lot of people taking this approach without any issues.

I can confidently say, that if you use reliable and compatible components you should be fine.


The first question to answer would be the link speed capabilities between the controller and the optical drive. This can be view using the System Information application. For example, my 2011 iMac shows the following for the optical drive.


Negotiated Link Speed is 1.5 Gigabit which is normal since most optical drives transfer data at less than this speed. What is important is the Link Speed of 3 Gigabit which is the maximum for the controller. HDD's require at least 3 Gigabit and SSD's require 6 Gigabit to operate at their maximum transfer rate. Anything less will often still work, but the drive will not be able to transfer date at its maximum speed. So, it would be worth the money to replace my optical drive with a HDD but not a SSD. (In my opinion)

My 2011 iMac shows the following for the HDD drive.


Here the Link Speed is 6 Gigabit, so a SDD replacement would be able to operate at its maximum transfer rate.

Note: I do know that 2011 iMac's can accommodate an internal SSD without removing the existing HDD or optical drive. I just used my iMac as an example to make the above images.

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