Q: imac frequent crashes

Exactly what year model is your 3.06 GHz iMac...

use > How to identify iMac models

or > Apple iMac Specs (All iMac Tech Specs) @ EveryMac.com

...and what RAM did you use when you upgraded it to 8GB...?

see > iMac: Memory specifications and upgrades

That panic was not caused by third-party software. If the problem is recurrent, the possibilities are:

1. A stale or corrupt kernel cache
2. A damaged OS X installation
3. A fault in a peripheral device, if any
4. Corrupt non-volatile memory (NVRAM)
5. An internal hardware fault (including incompatible memory)
6. An obscure bug in OS X

You may already have ruled out some of these.

Rule out #1 by booting in safe mode and then rebooting as usual. Note: If FileVault is enabled on some models, or if a firmware password is set, or if the boot volume is a software RAID, you can’t do this. Post for further instructions.

You can rule out #2 and #3 by reinstalling the OS and testing with non-essential peripherals disconnected and aftermarket expansion cards removed, if applicable. Sometimes a clean reinstallation may solve a problem that isn't solved by reinstalling in place.

Corrupt NVRAM, which rarely causes panics, can be ruled out by resetting it.

If your model has user-replaceable memory, and you've upgraded the memory modules, reinstall the original memory and see whether there's any improvement. Be careful not to touch the gold contacts. Clean them with a mild solvent such as rubbing alcohol. Aftermarket memory must exactly match the technical specifications for your model.

Apple Diagnostics or the Apple Hardware Test, though generally unreliable, will sometimes detect a fault. A negative test can't be depended on. Run the extended version of the test, if applicable.

In the category of obscure bugs, reports suggest that FileVault may trigger kernel traps under some unknown conditions. Most, though not all, of these reports seem to involve booting from an aftermarket SSD. If those conditions apply to you, try deactivating FileVault.

Connecting more than one display is another reported trigger for OS X bugs.

If your system is not fully up to date, running Software Update might get you a bug fix.

In rare cases, a malformed network packet from a defective router or other network device can cause panics. Such packets could also be sent deliberately by a skillful attacker. This possibility is something to consider if you run a public server that might be the target of such an attack.

If none of the above applies, make a "Genius" appointment at an Apple Store to have the machine tested. You may have to leave it there for several days. There isn't much point in doing this unless you can reproduce the panic, or if you can't, it happens often enough that it's likely to be repeated at the store. Otherwise you may be told that nothing is wrong.

Print the first page of the panic report and bring it with you.

Back up all data on the internal drive(s) before you hand over your computer to anyone. If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you know how to restore, and you have at least  two independent backups.) Don’t erase the recovery partition, if present.

Keeping your confidential data secure during hardware repair

*An SSD doesn't need to be zeroed.

See the link in my last comment about reinstalling the OS. The right version will be selected automatically. You don't have to pay again.

Seems this is a reaccuring event found all over the Apple Message boards with NO SUCCESSFUL solutions found to date. While the list above is admirable going through those painful hoops even the Genius Bar and the back room at Apple repair will be skipped. I just got my iMac back from the Genius bar claiming everything was repaired yet I don't think they bothered to do the simple test of rebooting the iMac after the repair. I had a misguided confidence like going to a restaurant and hoping the meal would be done right after a return. The moment I got my iMac home in about 60 secs after I launched Excel, Mail and Safari the iMac gave me a Gray screen and froze. I restarted the system a cleared the pram, the restarted and fixed the permissions then restarted using the Apple login to verify if it was a software conflict of my own doing using the basic Apple system and within 2 mins of just sitting there my screen gave me Zebra strips vertically and the system had crashed. Now after 3 tries the system won't even boot up at all. I have totally Black screen no bootup sound and completely dead!

I guess it's time to see a UBER Genius at Apple! The repairs below were billed at over $800 fortunately, I was smart enough to buy apple care but I've been out of a computer for a week now and still the system is dead. Perhaps this computer is now completely dead after all the repairs. It doesn't make any sense to me.

March 11, 2014

iMac 27 inch, Mid 2011

Processor 3.4 GHz Intel Core i7

Memory 16 GB 1333 Mhz DDR3

Graphics Radeon HD 6970M 2048 MB

Software OS X 10.9.2 (13C64)

Lists of repair items:

922-9872          Fan, Hard Drive

S1490LL/A          Hardware Repair Labor

661-5968          Card, Video, AMD Radeon HD 6970M, 1GB

661-6615          LCD PANEL 27 INCH WITH BLC

S1490LL/A          Hardware Repair Labor

Anonymous UUID:       EEB70928-4251-B44C-E507-337B7E35A48D

Sat Mar  1 13:08:49 2014

Machine-check capabilities: 0x0000000000000c09

family: 6 model: 42 stepping: 7 microcode: 40

signature: 0x206a7

Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz

9 error-reporting banks

Processor 0: IA32_MCG_STATUS: 0x0000000000000004

IA32_MC3_STATUS(0x40d): 0xbe00000000800400

IA32_MC3_ADDR(0x40e):   0x00003fff8b8fee3d

IA32_MC3_MISC(0x40f):   0x0000000000000001

Processor 1: IA32_MCG_STATUS: 0x0000000000000005

IA32_MC3_STATUS(0x40d): 0xbe00000000800400

IA32_MC3_ADDR(0x40e):   0x00003fff8b8fee3d

IA32_MC3_MISC(0x40f):   0x0000000000000001

panic(cpu 0 caller 0xffffff800a0dc6b9): "Machine Check at 0x00007fff8b8fee3d, registers:\n" "CR0: 0x0000000080010033, CR2: 0x00000000b0421000, CR3: 0x00000000438f003b, CR4: 0x00000000000606e0\n" "RAX: 0x0000000000000000, RBX: 0x00007f9591c00000, RCX: 0x00000000ffffffff, RDX: 0x0000000000000040\n" "RSP: 0x00007fff5887e708, RBP: 0x00007fff5887e7a0, RSI: 0x00007f9591c512b0, RDI: 0x0000000107378a00\n" "R8:  0x00007f9591c00000, R9:  0x0000000000000512, R10: 0x000000000d000011, R11: 0x0000000000000004\n" "R12: 0x0000000000000004, R13: 0x00007f9591c512b0, R14: 0x0000000107378a00, R15: 0x0000000107378a00\n" "RFL: 0x0000000000010246, RIP: 0x00007fff8b8fee3d, CS:  0x000000000000002b, SS:  0x0000000000000023\n" "Error code: 0x0000000000000000\n"@/SourceCache/xnu/xnu-2422.90.20/osfmk/i386/trap_native.c: 168

Backtrace (CPU 0), Frame : Return Address

0xffffff81db903dd0 : 0xffffff800a022fa9

0xffffff81db903e50 : 0xffffff800a0dc6b9

0xffffff81db903fb0 : 0xffffff800a0f3bcf

BSD process name corresponding to current thread: WindowServer

Mac OS version:

13C64

Kernel version:

Darwin Kernel Version 13.1.0: Thu Jan 16 19:40:37 PST 2014; root:xnu-2422.90.20~2/RELEASE_X86_64

Kernel UUID: 9FEA8EDC-B629-3ED2-A1A3-6521A1885953

Kernel slide:     0x0000000009e00000

Kernel text base: 0xffffff800a000000

System model name: iMac12,2 (Mac-942B59F58194171B)

System uptime in nanoseconds: 681126472605

last loaded kext at 278041244483: com.apple.filesystems.msdosfs          1.9 (addr 0xffffff7f8ca1f000, size 65536)

last unloaded kext at 344780946765: com.apple.filesystems.msdosfs          1.9 (addr 0xffffff7f8ca1f000, size 57344)

loaded kexts:

net.kromtech.kext.Firewall          2.3.5

foo.tap          1.0

foo.tun          1.0

com.AmbrosiaSW.AudioSupport          4.1.2

com.airgrab.driver.AirGrabFirewallModule          3.0

at.obdev.nke.LittleSnitch          4050

com.apple.driver.AudioAUUC          1.60

com.apple.driver.AppleHWSensor          1.9.5d0

com.apple.driver.AGPM          100.14.15

com.apple.filesystems.autofs          3.0

com.apple.driver.AppleBluetoothMultitouch          80.14

com.apple.driver.AppleMikeyHIDDriver          124

com.apple.driver.AppleMikeyDriver          2.6.0f1

com.apple.driver.AppleUpstreamUserClient          3.5.13

com.apple.kext.AMDFramebuffer          1.2.0

com.apple.iokit.IOUserEthernet          1.0.0d1

com.apple.driver.AppleHDA          2.6.0f1

com.apple.iokit.IOBluetoothSerialManager          4.2.3f10

com.apple.AMDRadeonX3000          1.2.0

com.apple.driver.AppleIntelHD3000Graphics          8.2.4

com.apple.kext.AMD6000Controller          1.2.0

com.apple.Dont_Steal_Mac_OS_X          7.0.0

com.apple.driver.AppleHWAccess          1

com.apple.driver.AppleLPC          1.7.0

com.apple.iokit.BroadcomBluetoothHostControllerUSBTransport          4.2.3f10

com.apple.driver.AppleSMCPDRC          1.0.0

com.apple.driver.AppleIntelSNBGraphicsFB          8.2.4

com.apple.driver.AppleBacklight          170.3.5

com.apple.driver.AppleMCCSControl          1.1.12

com.apple.driver.AppleSMCLMU          2.0.4d1

com.apple.driver.ACPI_SMC_PlatformPlugin          1.0.0

com.apple.driver.AppleThunderboltIP          1.1.2

com.apple.iokit.SCSITaskUserClient          3.6.6

com.apple.driver.AppleUSBCardReader          3.4.1

com.apple.driver.AppleIRController          325.7

com.apple.AppleFSCompression.AppleFSCompressionTypeDataless          1.0.0d1

com.apple.AppleFSCompression.AppleFSCompressionTypeZlib          1.0.0d1

com.apple.BootCache          35

com.apple.driver.XsanFilter          404

com.apple.iokit.IOAHCIBlockStorage          2.5.1

com.apple.driver.AppleUSBHub          666.4.0

com.apple.iokit.AppleBCM5701Ethernet          3.8.1b2

com.apple.driver.AirPort.Atheros40          700.74.5

com.apple.driver.AppleFWOHCI          4.9.9

com.apple.driver.AppleAHCIPort          3.0.0

com.apple.driver.AppleUSBEHCI          660.4.0

com.apple.driver.AppleACPIButtons          2.0

com.apple.driver.AppleRTC          2.0

com.apple.driver.AppleHPET          1.8

com.apple.driver.AppleSMBIOS          2.1

com.apple.driver.AppleACPIEC          2.0

com.apple.driver.AppleAPIC          1.7

com.apple.driver.AppleIntelCPUPowerManagementClient          216.0.0

com.apple.nke.applicationfirewall          153

com.apple.security.quarantine          3

com.apple.driver.AppleIntelCPUPowerManagement          216.0.0

com.apple.kext.triggers          1.0

com.apple.driver.IOBluetoothHIDDriver          4.2.3f10

com.apple.driver.AppleMultitouchDriver          245.13

com.apple.driver.DspFuncLib          2.6.0f1

com.apple.vecLib.kext          1.0.0

com.apple.iokit.IOSurface          91

com.apple.iokit.IOSerialFamily          10.0.7

com.apple.iokit.IOAcceleratorFamily          98.14

com.apple.iokit.IOBluetoothFamily          4.2.3f10

com.apple.kext.AMDSupport          1.2.0

com.apple.AppleGraphicsDeviceControl          3.4.35

com.apple.driver.AppleSMBusPCI          1.0.12d1

com.apple.iokit.IOBluetoothHostControllerUSBTransport          4.2.3f10

com.apple.driver.AppleHDAController          2.6.0f1

com.apple.iokit.IOHDAFamily          2.6.0f1

com.apple.driver.AppleBacklightExpert          1.0.4

com.apple.iokit.IONDRVSupport          2.4.1

com.apple.driver.AppleSMBusController          1.0.11d1

com.apple.iokit.IOGraphicsFamily          2.4.1

com.apple.iokit.IOAudioFamily          1.9.5fc2

com.apple.kext.OSvKernDSPLib          1.14

com.apple.driver.AppleSMC          3.1.8

com.apple.driver.IOPlatformPluginLegacy          1.0.0

com.apple.driver.IOPlatformPluginFamily          5.7.0d10

com.apple.iokit.IOFireWireIP          2.2.6

com.apple.driver.AppleThunderboltEDMSink          2.1.3

com.apple.iokit.IOSCSIMultimediaCommandsDevice          3.6.6

com.apple.iokit.IOBDStorageFamily          1.7

com.apple.iokit.IODVDStorageFamily          1.7.1

com.apple.iokit.IOCDStorageFamily          1.7.1

com.apple.driver.AppleUSBHIDKeyboard          170.15

com.apple.driver.AppleHIDKeyboard          170.15

com.apple.iokit.IOAHCISerialATAPI          2.6.1

com.apple.driver.AppleThunderboltDPInAdapter          3.1.7

com.apple.driver.AppleThunderboltDPOutAdapter          3.1.7

com.apple.driver.AppleThunderboltDPAdapterFamily          3.1.7

com.apple.driver.AppleThunderboltPCIDownAdapter          1.4.5

com.apple.iokit.IOSCSIBlockCommandsDevice          3.6.6

com.apple.iokit.IOUSBMassStorageClass          3.6.0

com.apple.iokit.IOSCSIArchitectureModelFamily          3.6.6

com.apple.iokit.IOUSBHIDDriver          660.4.0

com.apple.driver.AppleUSBMergeNub          650.4.0

com.apple.driver.AppleUSBComposite          656.4.1

com.apple.driver.AppleThunderboltNHI          2.0.1

com.apple.iokit.IOThunderboltFamily          3.2.7

com.apple.iokit.IOUSBUserClient          660.4.2

com.apple.iokit.IOEthernetAVBController          1.0.3b4

com.apple.driver.mDNSOffloadUserClient          1.0.1b5

com.apple.iokit.IO80211Family          630.35

com.apple.iokit.IONetworkingFamily          3.2

com.apple.iokit.IOFireWireFamily          4.5.5

com.apple.iokit.IOAHCIFamily          2.6.5

com.apple.iokit.IOUSBFamily          675.4.0

com.apple.driver.AppleEFINVRAM          2.0

com.apple.iokit.IOHIDFamily          2.0.0

com.apple.driver.AppleEFIRuntime          2.0

com.apple.iokit.IOSMBusFamily          1.1

com.apple.security.sandbox          278.11

com.apple.kext.AppleMatch          1.0.0d1

com.apple.security.TMSafetyNet          7

com.apple.driver.AppleKeyStore          2

com.apple.driver.DiskImages          371.1

com.apple.iokit.IOStorageFamily          1.9

com.apple.iokit.IOReportFamily          23

com.apple.driver.AppleFDEKeyStore          28.30

com.apple.driver.AppleACPIPlatform          2.0

com.apple.iokit.IOPCIFamily          2.9

com.apple.iokit.IOACPIFamily          1.4

com.apple.kec.corecrypto          1.0

com.apple.kec.pthread          1

Model: iMac12,2, BootROM IM121.0047.B1F, 4 processors, Intel Core i7, 3.4 GHz, 16 GB, SMC 1.72f1

Graphics: AMD Radeon HD 6970M, AMD Radeon HD 6970M, PCIe, 2048 MB

Memory Module: BANK 0/DIMM0, 4 GB, DDR3, 1333 MHz, 0x80CE, 0x4D34373142353237334348302D4348392020

Memory Module: BANK 1/DIMM0, 4 GB, DDR3, 1333 MHz, 0x80CE, 0x4D34373142353237334348302D4348392020

Memory Module: BANK 0/DIMM1, 4 GB, DDR3, 1333 MHz, 0x80CE, 0x4D34373142353237334348302D4348392020

Memory Module: BANK 1/DIMM1, 4 GB, DDR3, 1333 MHz, 0x80CE, 0x4D34373142353237334348302D4348392020

AirPort: spairport_wireless_card_type_airport_extreme (0x168C, 0x9A), Atheros 9380: 4.0.74.0-P2P

Bluetooth: Version 4.2.3f10 13477, 3 services, 23 devices, 1 incoming serial ports

Network Service: AirPort, AirPort, en1

Network Service: Ethernet 2, Ethernet, en0

Serial ATA Device: ST31000528AS, 1 TB

Serial ATA Device: OPTIARC DVD RW AD-5680H

USB Device: FaceTime HD Camera (Built-in)

USB Device: Hub

USB Device: Keyboard Hub

USB Device: Apple Keyboard

USB Device: BRCM2046 Hub

USB Device: Bluetooth USB Host Controller

USB Device: Hub

USB Device: IR Receiver

USB Device: Internal Memory Card Reader

Thunderbolt Bus: iMac, Apple Inc., 22.1

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