A couple of times a day my fans start spinning, ready for take off. The activity manager shows that Mail is eating up my CPU, 250% and more.

The console shows the following lines:

13-09-16 10:46:46,000 kernel[0]: Failed to open swap file 2
13-09-16 10:46:46,000 kernel[0]: vm_swap_create_file failed @ 42649 secs

And continues to do so for quite a long time. Is this a problem and if so how can I fix this?

OS Version: El Capitan 10.11.6

Hardware: MacBook Pro (Retina, 15-inch, Mid 2014), 16 GB RAM, 256 GB SSD.

  • Hi, to help me (and others) further help you, could you please advise what your computer hardware is, including type of storage and amount of RAM. Also, what version of OS X are you running? Thanks.
    – Monomeeth
    Sep 13, 2016 at 10:12
  • I can't find a directory called /var/vm... Sep 13, 2016 at 10:29
  • That one does exist, with the proper permissions. No files in there though. Sep 13, 2016 at 10:38
  • How much free space do you have on your SSD? And do you have any external drives connected?
    – Monomeeth
    Sep 13, 2016 at 10:48
  • @KeesdeKooter Did you search the system log for "I/O error" and how much free space is available on your system volume?
    – klanomath
    Sep 13, 2016 at 10:50

1 Answer 1


This could mean a number of things and yes, I would be concerned about it. First things first, ensure you have a working backup.

My next suggestion would be to reset both the PRAM/NVRAM and the SMC to see if this changes your computer's behaviour.

Reset your PRAM/NVRAM

Older Macs had what's called Parameter RAM (PRAM), newer Macs use Non-Volatile Random-Access Memory (NVRAM). Here’s how to reset your PRAM/NVRAM:

  1. Shut down your machine. Yes, a full shut down, not just logging out.
  2. Press the power button and then press the command-option-p-r keys. You have to make sure you press these keys before the gray screen appears or it won’t work.
  3. Hold those keys down until your Mac reboots again and you here the startup chime.
  4. Let go of the keys and let your Mac reboot normally.

Note: When you log back in you may need to readjust some of your system preferences (e.g. mouse speed, time and date/timezone, etc).

Reset the SMC

Your computer's System Management Controller (SMC) can also be reset. The instructions for resetting your SMC depend on three things:

  • Does your device run from a built-in battery?
  • Does your device run from a removable battery?
  • Does your device just run off power from the wall?

Now, since I don't know what computer you're using, I will provide the process for resetting the SMC in all three scenarios. Just use the one that is appropriate for your machine.

For MacBook Pros, MacBook Airs, and MacBooks where you can’t remove the battery on your own (i.e. it's a built-in battery), here’s what you do:

  1. Shut down your computer
  2. Keep the MagSafe adapter (power cable) plugged in.
  3. Press at the same time shift-option-control (on the left side of the keyboard) and the power button
  4. Let go
  5. Turn your computer back on with the power button.

For MacBook Pros, MacBooks etc that you can remove the battery from, here’s what you do:

  1. Shut down your computer
  2. Disconnect the MagSafe plug (power cable) from the computer
  3. Remove the battery
  4. Press the power button for 5 seconds and release
  5. Put the battery back in
  6. Reconnect the MagSafe cord (or power cable)
  7. Turn your computer back on with the power button

For iMacs, Mac Pros, Mac Minis, etc that only run from a power point in the wall

  1. Shut down your computer
  2. Unplug it from the power
  3. Press and hold the power button for 5 seconds
  4. Plug it back in and turn it on.

Hope this helps. Please report back and let us know.

  • Thanks. But unfortunately this does not make a difference. The message returned shortly after restarting the machine. Sep 13, 2016 at 9:47
  • Ok. I am interested in whether your fans still start spinning like crazy after taking these steps? Also, can you clarify whether you have any sort of virtual machine software installed (e.g. Parallels, Virtual Box, VM Ware Fusion, etc)? Finally, what result do you get returned when you go into Terminal and enter: sudo du -h -d1 /var/vm followed by your admin password? (It may be best for you to copy the bold bit and paste it directly into the Terminal window). Please post back the value you get.
    – Monomeeth
    Sep 13, 2016 at 10:27
  • du: /var/vm: No such file or directory. The fans are not spinning. And yes I do run VirtualBox. Sep 13, 2016 at 10:31
  • Ok, for now I am assuming the spinning fans are a totally separate issue to your swap file problem. Please report back if the fans start spinning like crazy again. Now, as far as the message returning shortly after restarting the Mac, do you know this because you were monitoring the console, or because some other issue presented itself? As for VirtualBox, how often do you run it? And, do you have anything set to automatically run after logging in? (You can check this by going to System Preferences > Users & Groups and selecting the Login Items tab.
    – Monomeeth
    Sep 13, 2016 at 10:52
  • 1
    As for what failing to open your swap file means, this basically means your Mac wasn't able to open up a swap file it had stored on your SSD. A swap file is basically OS X's way of dealing with running low on RAM - it saves the contents of RAM to a swap file on your SSD to make room for other apps/processes to use your RAM. When it's ready, it then swaps those contents around again. Macs with not enough RAM can end up creating lots of swap files. In your case 16GB should be plenty of RAM, even with VirtualBox running, although I don't know what else you use your Mac for.
    – Monomeeth
    Sep 13, 2016 at 11:25

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