Skip to main content

Apple's line of laptops for professional and power users. To date, the MacBook Pro line includes 13, 14, 15, 16, and 17-inch variants, with major revisions defined by unibody, Retina display, Touch Bar, and system-on-a-chip designs.

18260 Questions View all

Why is there a 750GB limitation with an optical drive bay HDD?

I would like to install a 1TB 2.5 HDD in the optical bay slot (Macbook Pro Unibody mid 2012).

I currently have a 500GB HDD in the optical bay and a 500GB SSD in the original hard drive bay.

I am curious to the 750 GB limitation that is noted in the description.

Product Code: IF107-080-3


The specs:

2012 macbook pro

10.10.3 OS X

4 GB Ram

2.53Ghz Quad I7

500 SSD has 1 OS partition

500 HDD 5400 RPM has 1 data partition

1 TB HDD 7200RPM has multiple partitions

Initial config:

500 SSD in HDD bay

500 HDD (original drive) in Optical bay

Benchmark SSD:Write 1024KB (451.306 MB/sec) Max


500 SSD boots properly

500 HDD reads and writes properly

New Configuration 1:

500 SSD in Optical Bay

1TB HDD in HDD bay


the 1 TB drive worked fine.

The 500 SDD (with the primary OS partition) had difficulty booting. After several attempts, the SDD booted to the OS. I attempted to run a benchmark test. The results were sporadic and had several force restarts.

Benchmark SSD:Not stable enough to officially record

New Configuration 2:

500 SSD in HDD bay

1 TB HDD in Optical bay


The SSD worked fine.

After booting to OS (using SSD), the 1 TB drive requested that I Initialize the drive. (Disk utility shows the individual partitions (disk1s1 etc) without any names) Occasionally, a single partition will mount and it is not always the same partition that mounts from that drive.

If a 1TB drive works, maybe it needs to be <7200 Rpm?

Answered! View the answer I have this problem too

Is this a good question?

Score 0


If you have a question about a particular product, please give a link to it so I don't have to spend ten minutes hunting it down. This forum is manned by volunteers, not by iFixit employees.


You could install your 500GB SSD in the optical bay and the 1TB HDD in the original HDD bay..


You could… but that would be counter-productive :( The optical bay bus runs slower than the other one on the machines. They were the same on later models.


Add a comment

1 Answer

Chosen Solution

That is very curious. Other opt-bat devices do not seem to have this limitation:

Was this answer helpful?

Score 2


This "optibay" from mcetech seemed to make the difference. The benchmark difference was only 2 -10 mb/s instead of hundreds when installed with the ssd. I haven't tried the 1tb, but I'm confident it would work with this optibay. Thank you for the alternative option!

I'm not sure why, but the ifixit model does have a hardware limitation. Though, I'm not sure why that is, I will confirm that it does.


I think the issue is drive height. Back in the day 1TB drives were higher so they couldn't fit the limit of 9.5mm of the carrier. So, if you have a drive that is 9.5mm or smaller and doesn't pull too much power it will work. Remember the SATA interface does not have any limits from a drive size. The systems BIOS & OS likewise have no bearing as well. I still recommend using the newest the system can support.


Add a comment

Add your answer

kcme94399 will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 0

All Time: 584