10.5.7 update: display, blue screen, and boot loop problems

The OS X 10.5.7 update has been out for enough time to be tested by a variety of users. On a good note, many have reported a notable speed increase, but others have reported a couple of outstanding problems. Apple has updated a lot in this release of OS X, and the prominent problems so far have to do with the updating process, which include display settings disappearing, boot loops, and updates resulting in the notorious blue screen.

Blue Screen

This update may automatically restart your computer up to three times during the update process, and for some people this has not happened but instead has hung on the first restart at the blue screen. Several people have reported waiting for the hang to resolve itself, but that has so far not been successful. When this happens, the fix so far has been to manually reset the computer.

1. Listen to the computer and be sure the hard drive is not being accessed.
2. Press and hold the power button until the computer shuts off.
3. Power on and hold the shift key to boot into safe mode.

Doing that procedure has helped a few people, and while some did not need to boot into safe mode, for others the computer would continually hang until they tried safe mode.

Blue screens have happened in the past during OS updates because of permissions and accessibility problems during the update. In order to reduce the probability of this happening, we recommend you update by using the following process (provided you've backed up your drive):

1. Don't use Software Update. Instead, download the standalone "Combo" updater.
2. Reboot into Safe Mode.
3. Run Disk Utility and perform a Permissions fix and hard drive repair.
4. Run the updater.
5. Immediately repair permissions again.

Display Resolutions are Incorrect

Another prominent issue seems to be certain display resolutions are disappearing, resulting in the computer outputting non-native display resolutions to the monitor. In most cases, instead of being able to choose 1920x1200 as the resolution (the native resolution for many widescreen displays), the computer will only output 1920x1080 (the maximum for HDMI connections). This seems to be a conflict in the drivers, since 1920x1080 is the maximum display resolution for HDMI connections.

There may be several approaches to fixing this problem. The first would be to try a PRAM reset, which can be done by holding the options-command-P-R keys all at once at reboot, and holding them down until the computer resets a few times, then releasing them and allowing the computer to boot normally.

If a PRAM reset doesn't work, try a workaround suggested by Apple Discussion board user "cizko", which is to install a screen output tweaking program called "SwitchResX" for fine-customization of monitor outputs. The program is a demo, but installing it, setting the screen resolution, and then optionally uninstalling it seems to clear the resolution problem the OS X update.

A word of note: some people have found that in using SwitchResX, the only way they were able to get things to work was by going to the "Timing Parameters" settings and checking "Use Simplified settings", and then changing the drop-down menu from "GTF" to "CTV-RB".

General Troubleshooting Steps

If you're experiencing problems after updating, try the following to see if you can clear the issue:

1. Boot into Safe Mode and run a permissions fix with Disk Utility.
2. Reset the PRAM.
3. Reinstall the update using the downloadable "combo" update (not any other), and following the "safe" method of installation mentioned above.

If you have other fixes for problems you've experienced with this update, please let us know: http://www.macfixit.com/contact.

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