13 Replies Latest reply: Dec 29, 2012 10:18 AM by Simon Abrams
sb3000 Level 1 (0 points)

I have a Macbook Air (1.8 GHz i7, 4 GB RAM, 250 GB SSD) and just installed Mountain Lion. Previous OS was Lion, final version. And suddenly my computer is bogging down and I get messages that say "Your Mac OS X startup disk has no more space available for application memory." I get these messages and my computer hangs--this has happened several times today and I've had to force restart.


It is not because I have too little hard disk space available, because 165 GB of my 250 GB hard drive is free. And it is not because I am running too many apps--I even got this message once with the only open app being Activity Monitor.


Here's what I've tried:


1. Disabling Java and Javascript

2. Repairing disk permissions

3. Verifying the disk (using Disk Utility)

4. Restarting

5. Running Omni Disk Sweeper (which confirms that most of my hard disk is free)


I have not turned off Spotlight or Backblaze.


The processes that keep spiking between 400 MB and 1 GB of memory (per Activity Monitor) are kernel_task, mds, and bztransmit (the last might be from Backblaze, but I've even had these messages when this process was using almost no memory).


Right now I've been able to use Safari long enough to file this question to Apple Support Communities, but I have only 8.7 MB of free RAM (per Activity Monitor), which makes no sense given the 4 GB RAM in my Mac and the fact that I'm running only Activity Monitor and only one window in Safari.


Suggestions appreciated!

MacBook Air, OS X Mountain Lion
  • David A. Gatwood Level 3 (580 points)

    Those errors typically mean that the hard drive is full or that the computer could not create a swap file for some other reason.  Try booting in recovery mode (or booting from an OS install disc) and running Disk Utility to check your boot volume for errors.

  • cozar Level 2 (340 points)

    I think it refers to virtual memory. Has nothing to do with total disk space as such. I would suspect a third-party installation messing up after the upgrade. Backblaze perhaps.

  • sb3000 Level 1 (0 points)

    Thank you, David and cozar. I restarted in recovery mode and ran Disk Utility, but the boot volume is fine--no problems at all. What is more promising is that I ejected my external drive (backup and archive, connected via USB 2). That seemed to reduce the memory pressure. So my guess it was either Spotlight indexing the external drive, or Time Machine trying to back up to it, or Backblaze trying to back up from it, that was the problem. I'll post more if I learn anything else. Thanks again for the help.

  • DFTeitel Level 1 (5 points)

    I'm pretty sure it's Backblaze. I have a retinaMBPro with Mountain Lion and 16 gigs of RAM, using very little of the CPU with only a few apps running, and I started getting the same message within minutes of updating Backblaze (to Activity monitor shows that about 80% of the CPU is free, and iStatPro confirms that about 80% is idle. I've contacted Backblaze and am waiting for a response.

  • Ola_M Level 1 (0 points)

    I have an iMac 27" with 8 Gb of RAM and 2T of HD, 940 Gb free, and get this message even after a clean install of Mountain Lion. The disk was fine with Disk Utility before install, and still is. The machin is very slow, and I can hear a lot of disk activity.

  • SecurityCatalyst Level 1 (0 points)

    Any updates from Backblaze?


    I have a comparable setup to you. After a month, finally decided to reload backblaze, and am experiencing the same results.

  • Fred Kahl Level 1 (5 points)

    Hi All,

    I am having the exact same issue on my brand new retina macbook. Left alone, the machine slows to a crawl and finally seizes up. I have 16 gigs of ram and plenty of free drive space. Apple support walked me through emptying caches, running disc utility and finally reinstalling mountain lion. I took it in to the store and they ran hardware diagnostics- everything checks out. Its a software issue, they say.


    The weird thing is that I have a non retina macbook Pro at work, and I'm getting the same thing- spinning beachballs until the machine seizes up. The only difference is that the non retina machine doesn't get the "Your Mac OS X startup disk has no more space available for application memory." alerts.


    Looking at activity monitor, I see three processes that start running away:


    -kernel task

    -Dynamic Pager


    Any help or advice is greatly appreciated!

  • Fred Kahl Level 1 (5 points)

    PS: I do not use backblaze

  • David A. Gatwood Level 3 (580 points)

    The kernel and default pager are going crazy because some process is using too much memory, and it is having to use disk space (virtual memory) as RAM to keep the app running.  In all likelihood, the misbehaving process is imagent.  See the following thread for more info:



  • DFTeitel Level 1 (5 points)

    In the end, I found that the problem wasn't Backblaze, at least in my case (they also said it wasn't). I think that it was Calendar and the delegated calendars of our Exchange Server. It seemed to be hoarding GBs of RAM somehow. Once I deleted all the delegates the problem went away. And it hasn't been a problem since I re-accessed those delegated calendars.

  • RPOH Level 1 (0 points)

    Hi, just another report on this saga. I have a MacBook Pro retina under ML 10.8.2. The problem of "OSX startup disk has no more ...." irritatet me for some time and Apple Assistance did not a winning answer. After various attempts and re-installation of ML (no effect) I looked at Activity Monitor and discovered that the Dashboard was driving the VM up to 724GB and the Swap to 59GB. I then searched for indication of this problem and found an entry which did mention the issue and suggested how to take Dashboard down temporarily (actually it did take it off the air permanently!.

    However, since then the VM in my case staid at a reasonable 300GB odd and I have not seen the warning again.

    It may be that the cause is an old widget, but I have not yet investigated which one might be the sinner, for that I need to recover Dashboard (probable another reinstallation).


    I just thought that this might be interesting for some of you, though probably there are several causes, which lead to this strange behaviour. Hopefully this will go away in the next update?!

  • Ola_M Level 1 (0 points)

    I found out my problems were due to CalendarAgent, see https://discussions.apple.com/message/19125367#19125367  and



    That fixed my problems.

  • Simon Abrams Level 1 (20 points)

    My problem is slightly different than you guys' - in my case, if I leave my MacBook Pro (summer 2012, 8GB RAM, 750GB hd, with 412GB available) up and running for more than 2-3 few days it gradually crawls to a halt, with many GB of page outs, no free memory, and bztransmit using massive amounts of virtual memory. It doesn't seem to matter how much content is being backed up either - at the time I took this screenshot, Backblaze was fully backed up, and had been for a few days. I never get the "out of memory" error that you guys are seeing, though - the machine just becomes highly unresponsive (talking like 30+ seconds to open a tab in Safari, or switch between apps - that sort of thing).


    I am using Exchange calendars too, to so I'm wondering if my issue could be related to that after all.Screen Shot 2012-12-28 at 12.14.51 PM.png