IMac – 2012 27″ iMac fan starts running at high speed when shut down and won’t stop

imacshutdown

My 2012 27″ iMac is working quite well, even the fan doesn't behave strange as along as the computer is running or is in sleep mode. But it becomes strange when I shut down the Mac, because when the machine is OFF, the fan runs riot.

This is how I shut it down:
I select the apple-symbol in the menu bar and click on "Shut Down…". After that I get a popup-window that tells me that without any further action the Mac would be shut down in 60 seconds (counting down). This window contains a checkbox where I can choose if I want to get all windows reopened after the next start (I don't want). I click on the right button that says "Shut Down". Then the screen turns black, and if I listen carefully I can hear some quiet noise form the harddisk, and after that I would expect that the machine would be completely off and emmits neither any light nor any noise.

This is true for light but not for noise. In exactly that moment when I would expect the end of all activities, the fan starts to run at highest possible speed. I didn't even know that it can run so fast and blow out so much air. But it does. And it wont stop. Even if I wait more than half an hour the fan keeps running at highest speed. And the Mac is NOT hot! When I touch it, it feels as cold as any other peace of metal that has room temperature.

The fan stops only in this two cases:

  1. I physically disconnect the power cable. After doing so, I can wait as long as I want (I tried 8 hours during night). In the very moment when I reconnect the power supply, the fan instantly starts running at top speed and won't stop again (I lost patience after 20 minutes and then I pulled out the plug again).

  2. I press the on/off-button on the back of the lower left corner of the Mac. In this case the fan stops on the spot and the startup-procedure beginns and everything is fine.

The fan also goes mad after long time in sleep-mode:
When I do normal work on my Mac (writing text, browsing in internet) I can hear the fan at a very low level. It is so quiet that I really must concentrate to hear it. When it is in sleep mode I don't even hear this low noise. I think the fan is stoped completely in this mode. But when the sleep-mode is lasting too long the fan jumps into high-speed mode too. I noticed this today morning. Yesterday evening I set the iMac in sleep mode by pressing the on/off-button on the back of the lower left corner. Then I was watching TV for aprox. 2 hours and then i left the room and went to bed. Fan was quiet at this moment. When I came back in the morning I found the mac with the fan running on highest possible speed.

This happened before:
The day before yesterday I bought a new usb-hub. When the Mac was in sleep mode I connected the hub's UBS-cable to the mac and then connected the hub's power supply to the outlet next to the one where the mac gets its power from. Then I turned on the Mac and everything was fine. I worked some time on it (I guess 1 hour) then I pressed the on/off-button to send it to sleep, but this time it was different:

The screen turned black as expected, but the mouse-pointer was still visible for aprox. 5 or 10 seconds. I didn't try to move the mouse in this moment, so I don't know if it would have reacted on mousemovement. Then also the mouse-pointer disappeared and everything was as expected. Then I was away for some hours and when I came back I tried to turn on the iMac by pressing the on/off-Button. But nothing happened. I tried pressing the button for a long time (1 min) and tried to press it fast in rapid succession but nothing happened. My iMac stayed off. So I pulled out the power plug, did wait for aprox. 1 minute and reconnected it (at this time nothing happened, also the fan didn't start). When I tried to press the on/off-button this time it did work. My iMac did start and worked fine. But since this episode the fan gets crasy when the machine is shut down. It does so with the new usb-hub connected but also without. The hub is working fine. I also tried to disconnect the second monitor and all usb-peripherals (except the apple-keyboard with numeric keypad)

Technical details:
iMac with 27" screen from late 2012
CPU: 2.9 GHz Intel Core i5
RAM: 16 GB 1600 MHz DDR3
GPU: NVIDIA GeForce GTX 660M 512 MB
OS: OS X 10.8.3 (12D78)
Physical storage: 120 GB APPLE SSD SM128E + 1000 GB APPLE HDD WDC WD10EALX-408EA0

(I asked this question here too: https://discussions.apple.com/thread/5020504)

This is the logs from console when shutting down and restarting after some seconds:

07.05.2013 15:31:02,924 com.apple.launchd.peruser.501[206]: (com.apple.PackageKit.InstallStatus) Throttling respawn: Will start in 5 seconds
07.05.2013 15:31:02,946 WindowServer[109]: CGXDeferSurfaces : Invalid source window 149
07.05.2013 15:31:04,000 kernel[0]: thunderbird (map: 0xffffff8034a473f0) triggered DYLD shared region unnest for map: 0xffffff8034a473f0, region 0x7fff90400000->0x7fff90600000. While not abnormal for debuggers, this increases system memory footprint until the target exits.
07.05.2013 15:31:04,882 WindowServer[109]: CGXDeferSurfaces : Invalid source window 56
07.05.2013 15:31:04,885 com.apple.launchd.peruser.501[206]: ([0x0-0x6006].com.apple.TextEdit[228]) Exited: Killed: 9
07.05.2013 15:31:04,886 librariand[257]: item update observer error: Connection invalid
07.05.2013 15:31:04,890 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,890 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,890 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,891 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,891 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,891 WindowServer[109]: dict count after removing entry for window 0x25 is 0
07.05.2013 15:31:04,893 com.apple.launchd[1]: (com.apple.qtkitserver[369]) Exited: Killed: 9
07.05.2013 15:31:04,904 com.apple.launchd.peruser.501[206]: (com.apple.talagent[230]) Exited: Killed: 9
07.05.2013 15:31:04,904 coreservicesd[36]: SendFlattenedData, got error #268435459 (ipc/send) invalid destination port from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=142
07.05.2013 15:31:04,913 com.apple.launchd.peruser.501[206]: ([0x0-0x33033].com.apple.AppleSpell[617]) Exited: Terminated: 15
07.05.2013 15:31:04,913 com.apple.launchd.peruser.501[206]: (com.apple.quicklook[822]) Exited: Killed: 9
07.05.2013 15:31:04,913 com.apple.launchd.peruser.501[206]: ([0x0-0x12012].com.apple.iTunesHelper[300]) Exited with code: 1
07.05.2013 15:31:04,913 com.apple.launchd.peruser.501[206]: (com.apple.mdworker.shared.04000000-0000-0000-0000-000000000000[797]) Exited: Killed: 9
07.05.2013 15:31:04,925 coreservicesd[36]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=101
07.05.2013 15:31:04,925 coreservicesd[36]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=281
07.05.2013 15:31:04,926 coreservicesd[36]: SendFlattenedData, got error #268435460 (ipc/send) timed out from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=151
07.05.2013 15:31:04,933 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,933 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,933 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,933 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,933 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:04,946 loginwindow[60]: DEAD_PROCESS: 60 console
07.05.2013 15:31:04,981 coreservicesd[36]: SendFlattenedData, got error #268435459 (ipc/send) invalid destination port from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=151
07.05.2013 15:31:04,998 airportd[836]: _doAutoJoin: Already associated to “SHAPP”. Bailing on auto-join.
07.05.2013 15:31:05,155 coreservicesd[36]: SendFlattenedData, got error #268435459 (ipc/send) invalid destination port from ::mach_msg(), sending notification kLSNotifyApplicationDeath to notificationID=135
07.05.2013 15:31:05,162 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:05,162 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:05,162 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:05,162 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:05,162 WindowServer[109]: CGXGetConnectionProperty: Invalid connection 27143
07.05.2013 15:31:05,184 shutdown[838]: halt by hubert: 
07.05.2013 15:31:05,184 shutdown[838]: SHUTDOWN_TIME: 1367933465 184417
07.05.2013 15:31:05,191 UserEventAgent[13]: Captive: [UserAgentDied:139] User Agent @port=45831 Died
07.05.2013 15:31:45,000 bootlog[0]: BOOT_TIME 1367933505 0
07.05.2013 15:31:47,000 kernel[0]: PMAP: PCID enabled
07.05.2013 15:31:47,000 kernel[0]: PMAP: Supervisor Mode Execute Protection enabled
07.05.2013 15:31:47,000 kernel[0]: Darwin Kernel Version 12.3.0: Sun Jan  6 22:37:10 PST 2013; root:xnu-2050.22.13~1/RELEASE_X86_64
07.05.2013 15:31:47,000 kernel[0]: vm_page_bootstrap: 4020482 free pages and 141054 wired pages
07.05.2013 15:31:47,000 kernel[0]: kext submap [0xffffff7f80735000 - 0xffffff8000000000], kernel text [0xffffff8000200000 - 0xffffff8000735000]
07.05.2013 15:31:47,000 kernel[0]: zone leak detection enabled
07.05.2013 15:31:47,000 kernel[0]: standard timeslicing quantum is 10000 us
07.05.2013 15:31:47,000 kernel[0]: standard background quantum is 2500 us
07.05.2013 15:31:47,000 kernel[0]: mig_table_max_displ = 74
07.05.2013 15:31:47,000 kernel[0]: TSC Deadline Timer supported and enabled
07.05.2013 15:31:47,000 kernel[0]: corecrypto kext started!
07.05.2013 15:31:47,000 kernel[0]: Running kernel space in FIPS MODE
07.05.2013 15:31:47,000 kernel[0]: Plist hmac value is    735d392b68241ef173d81097b1c8ce9ba283521626d1c973ac376838c466757d
07.05.2013 15:31:47,000 kernel[0]: Computed hmac value is 735d392b68241ef173d81097b1c8ce9ba283521626d1c973ac376838c466757d
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS integrity POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS AES CBC POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS TDES CBC POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS AES ECB AESNI POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS AES XTS AESNI POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS SHA POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS HMAC POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS ECDSA POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS DRBG POST test passed!
07.05.2013 15:31:47,000 kernel[0]: corecrypto.kext FIPS POST passed!
07.05.2013 15:31:47,000 kernel[0]: AppleACPICPU: ProcessorId=1 LocalApicId=0 Enabled
07.05.2013 15:31:47,000 kernel[0]: AppleACPICPU: ProcessorId=2 LocalApicId=2 Enabled
07.05.2013 15:31:47,000 kernel[0]: AppleACPICPU: ProcessorId=3 LocalApicId=4 Enabled
07.05.2013 15:31:47,000 kernel[0]: AppleACPICPU: ProcessorId=4 LocalApicId=6 Enabled
07.05.2013 15:31:47,000 kernel[0]: AppleACPICPU: ProcessorId=5 LocalApicId=255 Disabled
07.05.2013 15:31:47,000 kernel[0]: AppleACPICPU: ProcessorId=6 LocalApicId=255 Disabled
07.05.2013 15:31:47,000 kernel[0]: AppleACPICPU: ProcessorId=7 LocalApicId=255 Disabled
07.05.2013 15:31:47,000 kernel[0]: AppleACPICPU: ProcessorId=8 LocalApicId=255 Disabled
07.05.2013 15:31:47,000 kernel[0]: calling mpo_policy_init for TMSafetyNet
07.05.2013 15:31:47,000 kernel[0]: Security policy loaded: Safety net for Time Machine (TMSafetyNet)
07.05.2013 15:31:47,000 kernel[0]: calling mpo_policy_init for Sandbox
07.05.2013 15:31:47,000 kernel[0]: Security policy loaded: Seatbelt sandbox policy (Sandbox)
07.05.2013 15:31:47,000 kernel[0]: calling mpo_policy_init for Quarantine
07.05.2013 15:31:47,000 kernel[0]: Security policy loaded: Quarantine policy (Quarantine)
07.05.2013 15:31:47,000 kernel[0]: Copyright (c) 1982, 1986, 1989, 1991, 1993
07.05.2013 15:31:47,000 kernel[0]: The Regents of the University of California. All rights reserved.
07.05.2013 15:31:47,000 kernel[0]: MAC Framework successfully initialized
07.05.2013 15:31:47,000 kernel[0]: using 16384 buffer headers and 10240 cluster IO buffer headers
07.05.2013 15:31:47,000 kernel[0]: IOAPIC: Version 0x20 Vectors 64:87
07.05.2013 15:31:47,000 kernel[0]: ACPI: System State [S0 S3 S4 S5]
07.05.2013 15:31:47,000 kernel[0]: AppleIntelCPUPowerManagement: Turbo Ratios 3467
07.05.2013 15:31:47,000 kernel[0]: AppleIntelCPUPowerManagement: (built 12:18:39 Oct 18 2012) initialization complete
07.05.2013 15:31:47,000 kernel[0]: PFM64 (36 cpu) 0xf80000000, 0x80000000
07.05.2013 15:31:47,000 kernel[0]: [ PCI configuration begin ]
07.05.2013 15:31:47,000 kernel[0]: console relocated to 0xfc0020000
07.05.2013 15:31:47,000 kernel[0]: PCI configuration changed (bridge=17 device=4 cardbus=0)
07.05.2013 15:31:47,000 kernel[0]: [ PCI configuration end, bridges 13 devices 16 ]
07.05.2013 15:31:47,000 kernel[0]: AppleThunderboltNHIType2::setupPowerSavings - GPE based runtime power management
07.05.2013 15:31:47,000 kernel[0]: AppleThunderboltNHIType2::start - type 2 sleep enabled
07.05.2013 15:31:47,000 kernel[0]: AppleThunderboltNHIType2::start - SXFP method found
07.05.2013 15:31:47,000 kernel[0]: mbinit: done [128 MB total pool size, (85/42) split]
07.05.2013 15:31:47,000 kernel[0]: Pthread support ABORTS when sync kernel primitives misused
07.05.2013 15:31:47,000 kernel[0]: rooting via boot-uuid from /chosen: 8EBBF291-6BE4-3781-89A1-A85A5BCB9B6F
07.05.2013 15:31:47,000 kernel[0]: Waiting on <dict ID="0"><key>IOProviderClass</key><string ID="1">IOResources</string><key>IOResourceMatch</key><string ID="2">boot-uuid-media</string></dict>
07.05.2013 15:31:47,000 kernel[0]: com.apple.AppleFSCompressionTypeZlib kmod start
07.05.2013 15:31:47,000 kernel[0]: com.apple.AppleFSCompressionTypeDataless kmod start
07.05.2013 15:31:47,000 kernel[0]: com.apple.AppleFSCompressionTypeZlib load succeeded
07.05.2013 15:31:47,000 kernel[0]: com.apple.AppleFSCompressionTypeDataless load succeeded
07.05.2013 15:31:47,000 kernel[0]: AppleIntelCPUPowerManagementClient: ready
07.05.2013 15:31:47,000 kernel[0]: BTCOEXIST off 
07.05.2013 15:31:47,000 kernel[0]: BRCM tunables:
07.05.2013 15:31:47,000 kernel[0]: pullmode[1] txringsize[  256] txsendqsize[1024] reapmin[   32] reapcount[  128]
07.05.2013 15:31:47,000 kernel[0]: CoreStorage: fsck_cs has finished for group "18819130-6B54-415C-B9FA-7BE5E09C27B8" with status 0x00
07.05.2013 15:31:47,000 kernel[0]: thr 0xffffff8029d4faa0 Composite Disk alg="bloomclock" unit_nbytes=131072
07.05.2013 15:31:47,000 kernel[0]: Got boot device = IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/SATA@1F,2/AppleIntelPchSeriesAHCI/PRT1@1/IOAHCIDevice@0/AppleAHCIDiskDriver/IOAHCIBlockStorageDevice/IOBlockStorageDriver/APPLE SSD SM128E Media/IOGUIDPartitionScheme/Customer@2/CoreStoragePhysical/CoreStorageGroup/Macintosh HD
07.05.2013 15:31:47,000 kernel[0]: BSD root: disk2, major 1, minor 8
07.05.2013 15:31:47,000 kernel[0]: Kernel is LP64
07.05.2013 15:31:47,000 kernel[0]: IOThunderboltSwitch(0x0)::listenerCallback - Thunderbolt HPD packet for route = 0x0 port = 12 unplug = 0
07.05.2013 15:31:45,382 com.apple.launchd[1]: *** launchd[1] has started up. ***
07.05.2013 15:31:45,382 com.apple.launchd[1]: *** Shutdown logging is enabled. ***
07.05.2013 15:31:47,379 com.apple.launchd[1]: (com.apple.automountd) Unknown key for boolean: NSSupportsSuddenTermination
07.05.2013 15:31:47,000 kernel[0]: AirPort_Brcm4331: Ethernet address 8c:2d:aa:52:8b:c9
07.05.2013 15:31:47,000 kernel[0]: IO80211Controller::dataLinkLayerAttachComplete():  adding AppleEFINVRAM notification
07.05.2013 15:31:47,000 kernel[0]: IO80211Interface::efiNVRAMPublished():  
07.05.2013 15:31:47,000 kernel[0]: BCM5701Enet: Ethernet address 10:dd:b1:9c:7d:74
07.05.2013 15:31:48,596 airportd[31]: _processDLILEvent: en1 attached (down)
07.05.2013 15:31:48,000 kernel[0]: createVirtIf(): ifRole = 1
07.05.2013 15:31:48,000 kernel[0]: in func createVirtualInterface ifRole = 1
07.05.2013 15:31:48,000 kernel[0]: AirPort_Brcm4331_P2PInterface::init name <p2p0> role 1 this 0xffffff802b0a0800
07.05.2013 15:31:48,000 kernel[0]: AirPort_Brcm4331_P2PInterface::init() <p2p> role 1
07.05.2013 15:31:48,000 kernel[0]: Created virtif 0xffffff802b0a0800 p2p0
07.05.2013 15:31:48,694 com.apple.kextd[14]: Can't load /System/Library/Extensions/iavkfs.kext - no code for running kernel's architecture.
07.05.2013 15:31:48,698 com.apple.kextd[14]: Load com.pctools.iantivirus.kfs failed; removing personalities from kernel.
07.05.2013 15:31:48,717 com.apple.SecurityServer[17]: Session 100000 created
07.05.2013 15:31:48,000 kernel[0]: NVDAStartup: Official
07.05.2013 15:31:48,000 kernel[0]: NVDAGK100HAL loaded and registered
07.05.2013 15:31:48,000 kernel[0]: IOBluetoothUSBDFU::probe
07.05.2013 15:31:48,000 kernel[0]: IOBluetoothUSBDFU::probe ProductID - 0x828B FirmwareVersion - 0x0032
07.05.2013 15:31:48,000 kernel[0]: [BroadcomBluetoothHCIControllerUSBTransport][start] -- completed
07.05.2013 15:31:48,000 kernel[0]: Previous Shutdown Cause: 5
07.05.2013 15:31:48,000 kernel[0]: [IOBluetoothHCIController][staticBluetoothHCIControllerTransportShowsUp] -- Received Bluetooth Controller register service notification 
07.05.2013 15:31:48,000 kernel[0]: [IOBluetoothHCIController][start] -- completed
07.05.2013 15:31:48,782 com.apple.SecurityServer[17]: Entering service
07.05.2013 15:31:49,000 kernel[0]: AirPort: Link Down on en1. Reason 1 (Unspecified).
07.05.2013 15:31:49,000 kernel[0]: en1::IO80211Interface::postMessage bssid changed
07.05.2013 15:31:49,000 kernel[0]: DSMOS has arrived
07.05.2013 15:31:49,000 kernel[0]: [IOBluetoothHCIController::setConfigState] calling registerService
07.05.2013 15:31:49,000 kernel[0]: X86PlatformPlugin::setRingTable - No ring table found!
07.05.2013 15:31:49,000 kernel[0]: X86PlatformPlugin::configResourceHandler - Failed to set ring table!
07.05.2013 15:31:49,000 kernel[0]: [AGPM Controller] build GPUDict by Vendor10deDevice0fe0
07.05.2013 15:31:49,006 UserEventAgent[13]: Captive: [HandleNetworkInformationChanged:2435] nwi_state_copy returned NULL
07.05.2013 15:31:49,326 hidd[64]: Posting 'com.apple.iokit.hid.displayStatus' notifyState=1
07.05.2013 15:31:49,000 kernel[0]: macx_swapon SUCCESS
07.05.2013 15:31:49,328 com.avast.proxy[78]: Starting daemon.
07.05.2013 15:31:49,335 com.avast.proxy[78]: Error connecting to AV daemon: connect(): No such file or directory
07.05.2013 15:31:49,335 com.avast.proxy[78]: Error connecting to AV daemon: connect(): No such file or directory
07.05.2013 15:31:49,335 com.avast.proxy[78]: Error connecting to AV daemon: connect(): No such file or directory
07.05.2013 15:31:49,335 com.avast.proxy[78]: Error connecting to AV daemon: connect(): No such file or directory
07.05.2013 15:31:49,347 corestoraged[69]: 0x7fff70c8d180 unlockLVF: LVF=C5BB2D53-3C35-45A4-AA88-CD2136E061A5, "None", status = "Unlocked"
07.05.2013 15:31:49,355 loginwindow[60]: Login Window Application Started
07.05.2013 15:31:49,368 awacsd[74]: Starting awacsd connectivity-78.2 (Dec 16 2012 19:43:29)
07.05.2013 15:31:49,380 appleeventsd[70]: main: Starting up
07.05.2013 15:31:49,372 mDNSResponder[57]: mDNSResponder mDNSResponder-379.37 (Dec 16 2012 19:43:09) starting OSXVers 12
07.05.2013 15:31:49,383 com.apple.usbmuxd[44]: usbmuxd-296.4 on Dec 21 2012 at 16:11:14, running 64 bit
07.05.2013 15:31:49,384 awacsd[74]: InnerStore CopyAllZones: no info in Dynamic Store
07.05.2013 15:31:49,442 apsd[76]: CGSLookupServerRootPort: Failed to look up the port for "com.apple.windowserver.active" (1102)
07.05.2013 15:31:49,452 apsd[76]: CGSLookupServerRootPort: Failed to look up the port for "com.apple.windowserver.active" (1102)
07.05.2013 15:31:49,496 mDNSResponder[57]: D2D_IPC: Loaded
07.05.2013 15:31:49,496 mDNSResponder[57]: D2DInitialize succeeded
07.05.2013 15:31:49,515 systemkeychain[88]: done file: /var/run/systemkeychaincheck.done
07.05.2013 15:31:49,536 netbiosd[55]: Unable to start NetBIOS name service: 
07.05.2013 15:31:49,540 com.avast.proxy[78]: client.dropbox.com:https: nodename nor servname provided, or not known
07.05.2013 15:31:49,544 aosnotifyd[122]: bootstrap_look_up failed (44e)
07.05.2013 15:31:49,551 coreservicesd[36]: FindBestLSSession(), no match for inSessionID 0xfffffffffffffffc auditTokenInfo( uid=0 euid=0 auSessionID=100000 create=false
07.05.2013 15:31:49,555 mds[56]: (Normal) FMW: FMW 0 0
07.05.2013 15:31:49,569 locationd[61]: NOTICE,Location icon should now be in state 0
07.05.2013 15:31:49,603 coreservicesd[36]: FindBestLSSession(), no match for inSessionID 0xfffffffffffffffc auditTokenInfo( uid=0 euid=0 auSessionID=100000 create=false
07.05.2013 15:31:49,603 WindowServer[106]: Server is starting up
07.05.2013 15:31:49,607 WindowServer[106]: Session 256 retained (2 references)
07.05.2013 15:31:49,607 WindowServer[106]: Session 256 released (1 references)
07.05.2013 15:31:49,625 WindowServer[106]: Session 256 retained (2 references)
07.05.2013 15:31:49,626 WindowServer[106]: init_page_flip: page flip mode is on
07.05.2013 15:31:49,626 blued[73]: Read the UHE Info
07.05.2013 15:31:49,631 blued[73]: Read version 2 info.  Number of devices:1
07.05.2013 15:31:49,632 blued[73]: Class of device:     0x2580
07.05.2013 15:31:49,632 blued[73]: Device name: 'Apple Magic Mouse' length:18
07.05.2013 15:31:49,632 blued[73]: Finished reading the HID data
07.05.2013 15:31:49,632 blued[73]: Found a device with PID:0x030d VID:0x05ac
07.05.2013 15:31:49,648 com.avast.proxy[78]: kextstat -l -b com.avast.PacketForwarder | grep com.avast.PacketForwarder > /dev/null error (1)
07.05.2013 15:31:49,000 kernel[0]: com.avast.AvastFileShield: Started.
07.05.2013 15:31:49,956 com.apple.launchd[1]: (com.avast.account[83]) Exited with code: 2
07.05.2013 15:31:50,240 configd[19]: setting hostname to "Huberts-iMac.local"
07.05.2013 15:31:50,244 configd[19]: network changed: DNS*
07.05.2013 15:31:50,439 WindowServer[106]: mux_initialize: Couldn't find any matches
07.05.2013 15:31:50,458 WindowServer[106]: GLCompositor enabled for tile size [256 x 256]
07.05.2013 15:31:50,458 WindowServer[106]: CGXGLInitMipMap: mip map mode is on
07.05.2013 15:31:50,523 WindowServer[106]: WSMachineUsesNewStyleMirroring: true
07.05.2013 15:31:50,524 WindowServer[106]: MPServiceForDisplayDevice: Invalid device alias (0)
07.05.2013 15:31:50,524 WindowServer[106]: Display 0x042c0140: GL mask 0x1; bounds (0, 0)[2560 x 1440], 42 modes available
Main, Active, on-line, enabled, built-in, boot, Vendor 610, Model b005, S/N 0, Unit 0, Rotation 0
UUID 0x000006100000b00500000000042c0140
07.05.2013 15:31:50,524 WindowServer[106]: Display 0x1b52c36e: GL mask 0x4; bounds (-1280, 0)[1280 x 1024], 45 modes available
Active, on-line, enabled, Vendor 1e6d, Model 4adc, S/N 746c, Unit 2, Rotation 0
UUID 0x00001e6d00004adc0000746c00000000
07.05.2013 15:31:50,524 WindowServer[106]: Display 0x003f003d: GL mask 0x2; bounds (0, 0)[0 x 0], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 1, Rotation 0
UUID 0xffffffffffffffffffffffff003f003d
07.05.2013 15:31:50,530 WindowServer[106]: Created shield window 0x7 for display 0x042c0140
07.05.2013 15:31:50,531 WindowServer[106]: Created shield window 0x8 for display 0x1b52c36e
07.05.2013 15:31:50,532 WindowServer[106]: Created shield window 0x9 for display 0x003f003d
07.05.2013 15:31:50,534 WindowServer[106]: Display 0x042c0140: GL mask 0x1; bounds (0, 0)[2560 x 1440], 42 modes available
Main, Active, on-line, enabled, built-in, boot, Vendor 610, Model b005, S/N 0, Unit 0, Rotation 0
UUID 0x000006100000b00500000000042c0140
07.05.2013 15:31:50,534 WindowServer[106]: Display 0x1b52c36e: GL mask 0x4; bounds (-1280, 416)[1280 x 1024], 45 modes available
Active, on-line, enabled, Vendor 1e6d, Model 4adc, S/N 746c, Unit 2, Rotation 0
UUID 0x00001e6d00004adc0000746c00000000
07.05.2013 15:31:50,534 WindowServer[106]: Display 0x003f003d: GL mask 0x2; bounds (3584, 0)[1 x 1], 1 modes available
off-line, enabled, Vendor ffffffff, Model ffffffff, S/N ffffffff, Unit 1, Rotation 0
UUID 0xffffffffffffffffffffffff003f003d
07.05.2013 15:31:50,534 WindowServer[106]: CGXPerformInitialDisplayConfiguration
07.05.2013 15:31:50,534 WindowServer[106]:   Display 0x042c0140: MappedDisplay Unit 0; Vendor 0x610 Model 0xb005 S/N 0 Dimensions 23.50 x 13.23; online enabled built-in, Bounds (0,0)[2560 x 1440], Rotation 0, Resolution 1
07.05.2013 15:31:50,534 WindowServer[106]:   Display 0x1b52c36e: MappedDisplay Unit 2; Vendor 0x1e6d Model 0x4adc S/N 29804 Dimensions 14.80 x 11.85; online enabled, Bounds (-1280,416)[1280 x 1024], Rotation 0, Resolution 1
07.05.2013 15:31:50,534 WindowServer[106]:   Display 0x003f003d: MappedDisplay Unit 1; Vendor 0xffffffff Model 0xffffffff S/N -1 Dimensions 0.00 x 0.00; offline enabled, Bounds (3584,0)[1 x 1], Rotation 0, Resolution 1
07.05.2013 15:31:50,595 WindowServer[106]: GLCompositor: GL renderer id 0x01022647, GL mask 0x00000007, accelerator 0x0000408f, unit 0, caps QEX|QGL|MIPMAP, vram 512 MB
07.05.2013 15:31:50,599 WindowServer[106]: GLCompositor: GL renderer id 0x01022647, GL mask 0x00000007, texture units 8, texture max 16384, viewport max {16384, 16384}, extensions FPRG|NPOT|GLSL|FLOAT
07.05.2013 15:31:50,602 loginwindow[60]: **DMPROXY** Found `/System/Library/CoreServices/DMProxy'.
07.05.2013 15:31:50,615 hidd[64]: void __IOHIDLoadBundles(): Loaded 0 HID plugins
07.05.2013 15:31:50,616 WindowServer[106]: Unable to open IOHIDSystem (e00002bd)
07.05.2013 15:31:50,634 WindowServer[106]: Created shield window 0xa for display 0x042c0140
07.05.2013 15:31:50,634 WindowServer[106]: Display 0x042c0140: MappedDisplay Unit 0; ColorProfile { 2, "iMac"}; TransferFormula (1.000000, 1.000000, 1.000000)
07.05.2013 15:31:50,637 WindowServer[106]: Created shield window 0xb for display 0x1b52c36e
07.05.2013 15:31:50,638 WindowServer[106]: Display 0x1b52c36e: MappedDisplay Unit 2; ColorProfile { 3, "L1970H"}; TransferFormula (1.000000, 1.000000, 1.000000)
07.05.2013 15:31:50,662 launchctl[194]: com.apple.findmymacmessenger: Already loaded
07.05.2013 15:31:50,694 com.apple.SecurityServer[17]: Session 100006 created
07.05.2013 15:31:50,706 hidd[64]: CGSShutdownServerConnections: Detaching application from window server
07.05.2013 15:31:50,707 hidd[64]: CGSDisplayServerShutdown: Detaching display subsystem from window server
07.05.2013 15:31:50,721 loginwindow[60]: Login Window Started Security Agent
07.05.2013 15:31:50,779 SecurityAgent[208]: This is the first run
07.05.2013 15:31:50,779 SecurityAgent[208]: MacBuddy was run = 0
07.05.2013 15:31:50,792 WindowServer[106]: MPAccessSurfaceForDisplayDevice: Set up page flip mode on display 0x042c0140 device: 0x107258d10  isBackBuffered: 1 numComp: 3 numDisp: 3
07.05.2013 15:31:50,797 coreaudiod[209]: AHS_DefaultDeviceManager::SynchronizeDeviceList: the device list should never be empty - retrying
07.05.2013 15:31:50,809 WindowServer[106]: MPAccessSurfaceForDisplayDevice: Set up page flip mode on display 0x1b52c36e device: 0x107258b90  isBackBuffered: 1 numComp: 3 numDisp: 3
07.05.2013 15:31:50,833 SecurityAgent[208]: User info context values set for hubert
07.05.2013 15:31:50,000 kernel[0]: virtual bool IOHIDEventSystemUserClient::initWithTask(task_t, void *, UInt32): Client task not privileged to open IOHIDSystem for mapping memory (e00002c1)

Best Answer

As you have seen, all Apple products actually run even when you power them off. On iOS, the battery keeps time and on Macs, the SMC is responsible for knowing when the power button is pressed and if the Mac should start itself up due to a scheduled wake or power on being saved in the NVRAM.

If you called for service, Apple would likely focus on several things:

  1. Have you checked that the firmware and software is up to date.
  2. Does this happen every single time, or is it an occasional thing.
  3. Have you disconnected everything (including the mouse and keyboard) and tested to see if it's in any way related to a peripheral.

Assuming you can reproduce this at will (it happens every time), you would probably take steps to reset the SMC to ensure it's getting proper readings from the temperature sensors.

If after spending the 10 minutes it would take to read through each and every step (I feel it's important to perform the steps in order - even if they seem unrelated or unnecessary), I would expect them to want to run diagnostics to physically open the Mac to check the sensors and wiring. Your symptoms sure sounds like the SMC either is stuck in some loop and not reading the temp sensors. Failure to control the fans properly could also be a hardware issue where the SMC is receiving a signal where the correct action is to keep the fans not only spinning, but spinning at an elevated level.