My Mac constantly wakes itself up from sleep for apparently no reason. Middle of the night, middle of that day, it just can't stay asleep. Why? I ran pmset with the following results:

[redacted]:~ [redacted]$  pmset -g assertions
2015-01-26 08:27:29 -0800 
Assertion status system-wide:
   BackgroundTask                 0
   ApplePushServiceTask           0
   UserIsActive                   1
   PreventUserIdleDisplaySleep    0
   PreventSystemSleep             0
   ExternalMedia                  1
   PreventUserIdleSystemSleep     0
   NetworkClientActive            0
Listed by owning process:
   pid 72(hidd): [0x0000b0bc000906ce] 18:03:19 UserIsActive named: "com.apple.iohideventsystem.queue.tickle" 
   pid 26(powerd): [0x000000230008012c] 43:45:02 ExternalMedia named: "com.apple.powermanagement.externalmediamounted" 
Kernel Assertions: 0x10c=USB,BT-HID,MAGICWAKE
   id=501  level=255 0x4=USB mod=1/24/15, 12:48 PM description=EHC1 owner=AppleUSBEHCI
   id=503  level=255 0x100=MAGICWAKE mod=1/26/15, 6:47 AM description=en0 owner=en0
   id=504  level=255 0x8=BT-HID mod=12/31/69, 4:00 PM description=com.apple.driver.IOBluetoothHIDDriver owner=BNBTrackpadDevice
   id=506  level=255 0x8=BT-HID mod=12/31/69, 4:00 PM description=com.apple.driver.IOBluetoothHIDDriver owner=AppleBluetoothHIDKeyboard
  • What version of Mac OS X and what model Mac? Have you tried resetting or turing off the BT keyboard (take out the battery for a few minutes to reset)? If you have a late model Mac and Lion or later, perhaps Powernap (support.apple.com/en-us/HT5394) is doing its bit?
    – IconDaemon
    Jan 26, 2015 at 16:56
  • As answered below, it was the BT keyboard running out of batteries. Jan 26, 2015 at 19:40

1 Answer 1


As for what:

The message Kernel Assertions: 0x10c=USB,BT-HID,MAGICWAKE says it.

Also the ExternalMedia is set to wake it up over your USBbluetooth. connection.

So you have a device (BT keyboard) that does that.

As for why:

You BT track pad wakes up (do you have a Cat?) other BT devices interference, low battery... see this for more.

To test do "Allow Bluetooth devices to wake this computer" OFF.

If you have the Magicwake app installed, remove it.

  • Ah, yes I have a bluetooth keyboard and bluetooth trackpad, I think one or both is low on battery. Thanks! Jan 26, 2015 at 19:39

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .