It's pretty popular to replace ones optical drive* on the MacBook Pro with a HDD, but how serious are the risks?

*In most cases, you'd do this when installing a third-party SSD, but I'd like to leave any of those benefits out of this and isolate matters of the HDD and Superdrive.

I mean things like:

  • Overheating
  • Performance issues
  • Battery life
  • Warranty status
  • Weight increase
  • Upsetting Steve

Update: The above questions have been addressed in this question, but there is a more serious issue — potentially, a missing sudden motion shock sensor in the optical drive.

  • Note that some harddrives have their own sensor designed for this. You will want one of those drives. Aug 2, 2013 at 17:16

8 Answers 8

  • Overheating shouldn't be an issue. The SuperDrive probably runs hotter (when it's in use) since it has moving parts
  • An SSD would most likely improve performance (especially if you use it as your boot drive and place for applications)
  • Don't know about battery life, but I imagine if you you use this as your boot drive, and the stock hard disk as your "slave", you might actually see an improvement (again, fewer 'moving parts')
  • This will void your warranty, but if you're careful you might be able to get in and out without leaving evidence of tampering. Consult iFixit's guides for tips
  • I can't imagine there would be a noticeable weight difference.
  • Steve is dead, unless you're talking about Steve Zahn. Steve Zahn doesn't care what you do with your computer.
  • 1
    I agree with all of these except battery life. I get much worse battery life since I added an SSD and moved the hard drive to the optical bay. The performance increase more than makes up for it though (for me) Dec 1, 2012 at 2:07
  • Thank you Charles. In my case, for example, I already have an SSD running (I've modified my question), so I wonder how the HDD-replacing-SuperDrive action affects performance and battery-life alone. (I was joking when I mentioned Steve, RIP)
    – Baumr
    Dec 1, 2012 at 2:48
  • Either way, using the SSD at the boot and main storage for apps will keep the hdd used at a minimum. Not as minimum as the Superdrive, which few of us use anyway. Of course, you could always run two ssds but that is probably still cost prohibitive compared to the $ p/gb you get with an hdd. Your main issue will be the warranty I suppose, but like I said if you're careful and somewhat surgical you should be able to get around that. Dec 1, 2012 at 3:28
  • How to make that setup, specifying the drives in that arrangement? How does Disk Utility even see that I've attached a new SSD instead of my broken SuperDrive? Sep 11, 2013 at 20:16

I've done this to my own MacBook Unibody Late '08 earlier this year. In answering each query, this is what I've noticed...

  • Overheating: My machine has recently started over heating but it's hard to attribute this to the SSD/HDD combo. Most heat is coming not from where the SATA bays are located, but rather where the USB ports etc. sit.
  • Performance: has massively improved, but without a shadow of doubt, as the months have gone by, it has deteriorated. I still get lightning boot ups but apps are not as quick as they were. Please not that most 3rd party SSDs under Snow Leopard and above have no TRIM support. I've only just enabled mine through back door command line methods, which as with anything command line, may not be 'ideal' for the light-hearted user.
  • Battery life: has definitely decreased. In place of my optical bay is a 7200RPM hard drive, which takes more power than a standard 5400RPM. Also, given that you would be using your HDD a lot, unlike your superdrive which you use more occasionally than constantly (I'm assuming), you can expect some decrease.
  • Warranty: Will be severed!
  • Weight: the SSD is lighter than the original HDD. However, my new HDD and superdrive weight similar, the HDD 'feeling' heavier.

I've just posted a query about my machine as I think the SSD is causing some issues. The response to that may shed some further light on the topic.

  • Sorry I missed that quote. Yes, this is a problem but I was told to put the HDD in the Optical Bay. This was based on advices I was given to do with speeds. Recently I noticed when holding the laptop from under the optical bay, I could feel the HDD spins the more pressure I applied. It is a potential problem indeed. I guess if their are no link speed issues, it would make sense to keep the SSD in the optical bay, but I'm not entirely sure.
    – infmz
    Dec 1, 2012 at 15:56
  • It depends on your computer, see this: SATA speeds in SuperDrive and HDD bay
    – Baumr
    Dec 1, 2012 at 16:10
  • Thanks. Then I should've kept mine in the Optibay as its' an older, slower mac with SATA II. Mind you, after some tests just now, I'm starting to think that my HDD could be struggling, possible/partly due to it spinning while moved etc
    – infmz
    Dec 1, 2012 at 16:40

RE: voiding the warranty. When I recently bought my non-retina 13" MBP, I told several of the Apple Store people that I planned to swap out the HDD for the SSD I took from my now-dead (logic board) 15" MBP A1211, and that I realized I would void the warranty. They all told me that Apple considers the two drive bays "user replaceable" and that doing what I planned would NOT void the warranty. Specifically, I could put any SATA device in either bay. Anyone test this info?

  • Interesting stuff, I can't verify, but I'll ask around
    – Baumr
    Feb 1, 2013 at 11:08
  • 2
    The warranty says it doesn't cover damage due to unauthorized / untrained work. In the case where normal tools are needed (where pentalobe, tri lobe, sealed / locked would be not normal), your warranty should cover anything where you or someone else didn't cause damage. Think of it like this, if they could imagine the screen failing even if you didn't put a second hard drive in, why would they deny warranty coverage? Now, if you blew the optical bay cable and there happened to be some power hungry HDD - your warranty claims might be set aside, but that's not what I see being asked here.
    – bmike
    Feb 1, 2013 at 18:35

I can confirm that for the MBP Apple does not have a problem with users changing the drives. It does NOT void the warrantee.

My experience: I have replaced the disk drive with a 512G SSD and replaced the optical drive with a 1TB disk drive. I suspect that airflow is impacted as I feel that I run a bit hotter than before but I'm not really sure.

Battery life is better if I'm not churning the fixed disk (ie only using the SSD or cache).


I have a 2011 MBP 13" with SSD and HDD attached into SuperDrive with LMP Disk Doubler (http://www.mzone.sk/disk-doubler-3653)

  1. Overheating - Didn't notice any overheating.

  2. Performance issues - Works great. Made symbolic links to SSD home dir

  3. Battery life - Maybe an overall 5-10min decrease.

  4. Warranty status - I was in an App Store

  5. Weight increase - No


I have a 2010 MBP 15" with two Seagate Momentus XT 750GB hybrid hdd's (Removed optical drive - OWC website) and is being used for music creation using Pro Tools. It gets so hot that you have to stop what you are doing sometimes for larger sessions and save and close. Turn everything off and reopen session. Definitely the hybrid drives causing the problem and it is extremely noisy when this is happening thus hurting music creation process. Battery life NO GOOD. So, my purchase should've been two 1TB SSD hard drives which are now available and that would have solved my issues. Not most people but mine definitely. Good Luck

  • Try SMC fan control to boost the fan before things get warm? and lift the laptop off the table to make the heat dissipate more) Mar 19, 2014 at 12:54

I moved the existing 750GB 7200RPM HDD from its factory location to the optical bay. I then installed a new 256GB SSD in the HDD's bay. I booted to recovery mode and copied the contents from the HDD to the SSD, then told the MBP to boot from the SSD.

After that was all done, I reformatted the HDD and now only use it for extra storage. Mostly VMWare Images. It is configured to to boot un-mounted. When I want to use it, I run a mount command in my terminal window and it spins up and then is listed as an available drive on my desktop. When I am done with it I unmount it by right-clicking on it, and it spins down after one minute.

During normal use, if I am not accessing it, it spins down after one minute.

Overall I am very happy with the setup.


It depends on your Macbook Pro. I have first hand experience in this area regarding Apple's policies (many times).

The rule of thumb is: if the part is "user replaceable" then you can change it out yourself. If it is not, or if you damage your system while performing the upgrade, then it technically voids your warranty.

Your MBP's manual will list the user replaceable parts. Just google "Macbook Pro" plus the model designator (i.e. Macbook Pro 15-Inch Early 2011). You can find this information in the Apple Menu under "About This Mac".

Some Apple Retail Genius Teams are lenient in this regard and will diagnose and repair if your component is not the source of the issue. However it is a grey area.

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