Member Avatar for Lightninghawk

Unit:

2007 iMac with OS X

Problem:

Will not boot. Upon pressing power button it attempts to go through startup procedure then grey-screen and error message (You Need to restart your computer. Hold down the power button until it turns off, then press the power button again.)

I have come to understand this is called a "Kernel Panic"

I have been researching this issue all day. I cannot get it to safe boot by pressing the shift key. It does pull a progress bar but ultimately fails and returns to the kernel panic.

I have attempted to start from the CD to attempt utility disk, but I cannot get it to boot from CD. I have held the C key down. I have pressed it repeatedly. I have used it in combination with the alt/control/command keys. All have failed.

If anyone has any idea what might can be done I thank you in advance for your assistance.

~Daniel

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  • Latest Post Latest Post by dfxgrid12

Dani AI

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Short expert summary and next steps tailored to ’s situation (kernel panic at boot, Safe Boot shows progress then still panics, CD boot not working). Kernel panics are the OS telling you something low-level failed — common culprits are bad/loose RAM, a failing hard drive, incompatible kernel extensions or device drivers, or failing logic-board/GPUs. The official Apple troubleshooting flow starts by isolating software from hardware and then running hardware tests if software isolation fails. (support.apple.com)

Concrete, ordered checks to try now (fastest → more intrusive):

  • Remove everything nonessential (all USB devices, printers, external drives, PCI cards) and try powering on again — third‑party hardware often triggers panics. If you added RAM or other parts recently, remove or reseat them and try one stick at a time. (support.apple.com)

  • Retry Safe Boot correctly: power off, then power on and hold the left Shift key immediately until the login window (wired keyboard recommended). Safe Boot disables third‑party kexts and runs a disk check; if this succeeds you can run Software Update and Disk Utility First Aid. If it still panics early, that strongly points to hardware. (support.apple.com)

  • To run Disk Utility from install media: use Startup Manager (hold Option at power on) to pick a boot DVD/installer. If the DVD doesn’t appear, the disc or optical drive may be bad — try a known‑good retail OS X install disc or another Mac to test the DVD. If you have another Mac, use Target Disk Mode (hold T at startup) to mount the iMac’s drive and run Disk Utility from the host Mac. (support.apple.com)

If those fail, do these firmware/hardware checks:

  • Reset NVRAM/PRAM (hold Option‑Command‑P‑R at startup) and reset the SMC for the iMac (unplug power for ~15 seconds then plug back in and wait 5 seconds before powering on) — both are standard safe steps. Run Apple Diagnostics (hold D at startup) to get hardware error codes if present. (support.jamf.com)

If you can get a command prompt, run a filesystem check from single‑user mode (hold Command‑S at boot) and repeat until clean:

/sbin/fsck -fy
reboot

That often fixes directory problems that cause boot panics; otherwise capture Apple Diagnostics codes or panic logs and consider a drive replacement or service. (osxdaily.com)

As suggested, booting to installer and running Disk Utility is the right next step — the additions above cover timing/keys, what to try when the DVD or drive won’t show, how to isolate RAM, and how to run low‑level checks. If multiple attempts fail or Apple Diagnostics reports hardware errors, the machine likely needs a drive or logic‑board repair. Ignore ’s quip — these iMacs are repairable if the failing component is identified.

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Member Avatar for jingda

Hi Daniel,

To boot your iMac from a CD, insert the disk into your Mac and restart it. When it boot up, hold down option key until you see a lock ( in some case ). If not, you will see a white screen and an image of your internal hard disk and the mac osx install disk. Click on the disk and follow the onscreen instructions. Try repairing your disk using the disk.

If it fails, bring your iMac to an Apple service technician for help.

Member Avatar for dfxgrid12

Ouch, people still use these?

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