Wait it out
For some users just waiting it out and allowing the problem to correct itself has been the answer. In many cases, such as the blue screen experienced with leopard, users have just not waited long enough for boot problems to self-correct. If the problem does not correct itself after several hours, then try something else.
Run permissions fixes and drive repair Boot off a utility disk (second boot drive, Leopard DVD, or third-party disk utility) and run both a permissions fix and a repair on the boot drive. This should hopefully find problematic files and correct them so the computer has access to them on boot. Several users have had success with this. Apple Discussions poster alphaNerd wrote:
"How I fixed it was holding down the "Option" key while booting up and chose another drive, in my case, Techtools eDrive. Since TechTools is not compatible with Leo yet, I used my Disk Utility and fixed the disk permissions AND ran disk repair."
Disconnect external devices Temporarily disconnect any USB, FireWire other otherwise-connected external peripherals then re-attempt startup.
Workaround:
Perform an Archive and Install off the leopard DVD, and then immediately update to 10.5.3. If for some reason absolutely nothing works, performing an Archive and Install will get a fresh and unaltered version of Leopard running on the system, which can then be updated. This will save user settings and preferences, as well as the home folder and get the computer running again.
Other potential fixes:
Startup in Safe mode: Hold the shift key while rebooting your Mac, then just restart normally.
Reset NVRAM/PRAM: Shut down your Mac, then start it back up while immediately holding the following keys: Command, Option, P and R. Hold the keys down until the computer restarts and you hear the startup sound for the third time.
Check for problematic login/startup items: Startup in safe mode (hold the "Shift" key while you startup). Next, go to the Accounts pane of System Preferences and click the "Login items" tab. Select all the login items and click Remove, then restart. Also, check the /Library/StartupItems and /System/Library/StartupItems folders and remove any third-party items.
Look for problematic kernel extensions: Boot in Safe mode, and look in the folder /System/Library/Extensions for any third-party kernel extensions (files that end in .kext). Remove the kernel extensions and check for persistence of the issue.
Good Luck
P
After my computer froze during the v10.5.3 upgrade, I held the power button down to turn it off and then restart. Since it was turned off then the computer hasn't been usable since. So far this is what I have done to try to remedy the issue:
- Reset PRAM and NVRAM
- Using Single User Mode, deleted possible troubling files from Application Enhancer
- At Apple Store, AppleCare rep booted to a different hard disk and ran Disk Utility (found and repaired numerous errors), still the computer will not run.
- Attempted to boot from Tiger DVD that came with computer (by booting with the option key and selecting dvd), the computer goes into kernel panic.
I've tried everything that I could find, but still no luck! This is the symptom (as it has been since the day I installed the 10.5.3 update)
_I turn on the computer, the gray screen appears with the Apple Logo. After that, the spinning loading symobl begins to spin underneath the logo. Then it spins continually with no end, it has gone on for an hour or more before I turned off the computer._
Please, somebody, give me a solution! I have a presentation stuck on the computer that I need very soon! Apple is sending me a Leopard DVD in the mail (my other one is gone), but the 5-7 day wait will have me fail a project.
Thank you,
Alex.

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