The hard disk in my Mid-2009 MacBook Pro crashes intermittently.
In Activity Monitor, the disk activity flatlines and no data is written or read for a period of time, usually between 15 seconds and one minute.

The beachball appears and the computer is fairly unresponsive.
The active/current app will often appear as "Not responding" in the process list.
I have not been able to accurately induce it, and seems to occur fairly random although it does happen more frequently during periods of sustained disk activity. Watching YouTube videos, is almost certainly guaranteed to induce a freeze, as does Photo Stream syncing.

This started happening when I changed over to an SSD late last year, and after finding other people with my model of laptop, reporting the exact same issues I was convinced that an EFI update to the mid-2009 MBPs was the culprit. After Mountain Lion was released, I swapped to a new (not the original) HDD for a fresh install OS X and much to my surprise, it is still happening. I think it might even be worse (the duration feels greater).

I have absolutely no idea what is causing this or even how to troubleshoot it any further.

  • I have the exact same problem. This happens from a few times a week to a few times a day. This is in fact related to the SSD, but I haven't been able to solve it. I have a mid-2009 MBP too. – Kordonme Jul 30 '12 at 9:03
  • Me too. I haven't tried switching to another HDD yet, though. What make and model is your SSD of? And the "new" HDD? Could be interesting for those that might to be able to answer. – Manne W Aug 6 '12 at 20:10
  • Originally I tried two different 3Gb/s Mercury SSD from Macsales/OWC. Then an OCZ Vertex 2. HDD is a 500GB Seagate Momentus – Mike Aug 9 '12 at 3:08

I put the SSD in the optical bay and it seems to be working perfectly.


I had the same problem, but it disappeared when I reinstalled Lion. EDIT: If it's still occurring with a different OS, then it could be a hard drive problem. We have SMARTReporter installed on all our computers, and for the last 6 months it has been reporting I/O errors on one of our MacBook Pros. Just last week the hard drive finally failed. Try the trial version of SMARTReporter, and see what it says.


  • The user has tried switching OS's it seems to no effect – Simon Sheehan Aug 22 '12 at 4:26
  • Good point. It could indicate a failing hard drive then. – daviewales Aug 22 '12 at 4:49
  • Thanks for your suggestion. I've been running SMARTreporter for a couple of days now, but it hasn't detected any problems. – Mike Sep 23 '12 at 23:46
  • When I was experiencing similar issues, I read that it could be related to either Time Machine backups misbehaving, or Spotlight misbehaving. However nothing I tried really helped the issue until I installed Mountain Lion. (But even that doesn't appear to have worked in your case.) – daviewales Sep 27 '12 at 7:34

I too had this issue, but can't figure it out. Mid 09 MBP had a solid plugged 160GB 5400RPM original HDD (apple rebranded seagate drive) so I decided instead of trying to muck through and clean it up, I'd replace it with a 640GB 7200RPM drive, as well as upgrade its stock 2GB RAM to the maximum 8GB capacity. After all was said and done the computer was running great with Mountain Lion (up from the original Snow Leopard) however it periodically just stops running. Not slow, just frozen. No beach ball either. It makes no sense. It has all of the updates that it possibly can get too.

The only thing that really stands out different from what others described is that I used a Retina MBP 15" (mid 12) for the installation - I had the new drive connected via USB/SATA adapter since the rMBP has much faster internals - it installed in about 20 min. After everything was all done I installed the newly imaged drive into the 09 MBP and it booted up with no problems. Everything appeared to be working great. However out of nowhere it totally freezes - not even showing a beach ball. Haven't checked activity monitor to see the hard drive activity, but everything else checks out OK. Any input would be greatly appreciated.

  • This is really better as a comment as it is not an answer – Dave M Jan 15 '13 at 18:02

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