My Mac Won’t Start! - A Tiny Troubleshooting Guide

Ben Greiner -

In 2006 CreativeTechs and Forget Computers collaborated on a great little pocket guide (a PocketMod actually) titled MyMacWontStart-PocketMod.pdf (click the link to download or see the copy-and-pasted version below — included a newly added Step 5).

Although one might think a guide from 2006 would be outdated, the recommendations are still valid and we recently received a support request from someone who had our book in China!

Catherine had our pocket guide but needed a little more assistance. Fortunately, we were able to help and she's back on her Mac! In Catherine's own words...

"You put the suggestions in words I could understand and the instructions in easy to follow sequences.  Keep up the good work. And, thanks again for rescuing my computer and alleviating its ailments."


My Mac Won’t Start!
A Tiny Troubleshooting Guide


What’s The Problem?


Empty Blue or Grey Screen

Commonly caused by disk or permission problems, 3rd-party software problems, or occasional hardware issues.

Recommend: Proceed with Fixes 1-5. 


“No” Sign, Broken Folder, Flashing “?”

Indicates your Mac can’t find or use the needed System. May indicate disk problems.

Recommend: Skip to Fixes 3 & 4. 


Black Screen, No Sound

Your problem may be caused by power issues, a dead logic board battery, bad RAM, or other hardware issues.

Recommend: Turn to “Still Need Help?”


Fix 1: Start in Safe Mode
Startup Key: Shift

  1. Hold down Shift while you turn on your Mac.
  2. Release Shift when you see a gray Apple with a spinning gear.
  3. Done properly, the words “Safe Boot” should appear during startup or in the login window. Tip: Starting in Safe Mode takes longer than starting up normally because the system performs a directory check on the startup disk. Be patient.
  4. To leave Safe Mode, restart the computer, without holding any keys during startup.


Fix 2: Single-User Mode
Startup Keys: Command () + S

  1. Hold down Command-S while you turn on your Mac. You should see a black screen with white text. Don’t panic.
  2. At the prompt type: fsck -fy Press return. If you receive the message “File System was Modified,” repeat step 2 until it says “No problems were found.” 
  3. Type reboot and hit return.


An Alternative Solution: AppleJack

  1. If you installed AppleJack (before your Mac has problems) the process is simpler:
  2. Type: applejack auto restartand hit return.
  3. Wait several minutes. Your Mac will restart when repairs are completed. Available at


Fix 3: Start off Apple CD/DVD 
Startup Key: C

  1. Insert a Mac OS X Install disc. Tip: Hold down the mouse button while you turn on your Mac to open the CD tray.
  2. Hold down the C key while you turn on your Mac. Let go when the gray Apple appears.
  3. Mac OS X 10.2.x through 10.3.x: Choose Installer > Open Disk Utility.
    Mac OS X 10.4.x through 10.6.x: Choose Utilities > Disk Utility. 
  4. Select your hard drive icon on the left and click Repair Disk in the First Aid tab. Repeat until your disk reports no errors.
  5. When your disk reports no errors, click Repair Disk Permissions.
  6. Reboot your Mac without holding any keys during startup. Tip: In additional to Apple’s tools, consider purchasing Disk Warrior from


Fix 4: Target Disk Mode
Startup Key: T


When other techniques don’t work, Target Disk Mode lets you access your Mac’s hard drive from another computer. This lets you perform additional diagnostics, repairs, or backup important work files.

  1. Hold down the T key while you turn on your Mac. Let go when you see a FireWire icon on the screen.
  2. Connect the troubled Mac to a good Mac via a FireWire cable.
  3. Open Disk Utility on the good Mac (located in Applications/Utilities).
  4. Select the troubled Mac’s disk icon on the left and click Repair Disk in the First Aid tab.
  5. If possible, recover or backup important data files if the troubled Mac’s drive is visible on the good Mac’s desktop.

Fix 5: Zap PRAM
Startup Keys: Command (+ Option + P + R

We recently ran into a blue screen issue where the only thing that would fix the problem was zapping the PRAM (even though the computer would Safe Boot.)

  1. Hold down the Command (+ Option + P and R keys while you turn on your Mac. 
  2. Release these keys after the Mac restarts and you hear the startup sound for the second time.
  3. Details here:

Still Need Help?

If these quick troubleshooting steps don’t fix the problem, it’s time to look elsewhere:


If all else fails... bring in the big guns!

Turn to Forget Computers for expert Macintosh and iOS consulting and support.

Have more questions? Submit a request


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