iMac won't shutdown after installing Mavericks. ack!

[MacDoxy]

iMac 20 inch Mid 2007 2.4 ghz C2D
goes to greyscreen after clicking shutdown.

just updated to Mavericks from SL.

any ideas? TIA

[RAMd®d]

Have you tried booting into Safe Mode (hold the Shift key down while booting)?

As soon as it's booted into Safe Boot, shut it down and see if that works.

Besides running Disk Repair when it's booting up, there might be something hanging up Shutdown that's not loaded when going into Safe Boot.

I'd also run DiskWarrior, if possible.

Then there's reinstalling Mavericks.

How did you install it? Over another OS? Nuke and Pave?

Are you at 10.9.4?

[WHiiP]

Download and run the Combo Updater for 10.9.4. http://support.apple.com/kb/DL1755?viewlocale=en_US&locale=en_US

Your PRAM battery may need replacing. Unfortunately it is under the glass.

[Chakravartin]

A hang on a gray screen when you try to reboot is typically from a background program that refuses to quit. The system will send a kill command to troublesome programs, but a malfunctioning program may not take the kill command.

I'd start by cleaning out user caches. Sometimes programs stall because of obsolete or corrupt cache files screwing them up and Mavericks seems prone to problems immediately after upgrading from any previous OS if the user caches aren't tossed. You can use Onyx for that.

Also, remove all login items from the Users & Groups settings.

And it's a long shot, but you should confirm in the Disk Utility that you have journaling enabled on your boot drive. I just saw that symptom on a Retina MacBook Pro and it was due to journaling somehow having been disabled.

...

Those are the most likely things to cause problems immediately after upgrading to Mavericks. You might also have crummy 3rd party Extensions/LaunchAgents/LaunchDaemons in the /Library folder, but I hesitate to recommend removing those items without more info.

[anonymouse1]

Onyx is free.

[ka jowct]

Mavericks is more of a change than an upgrade.

[MacDoxy]

i ran repair permissions and it hung on a string that was saying something about printers. so i uninstalled all the printer software and that seems to have worked it out.
RP doesn't hang anymore and it shuts down normally now. now i just have to see if a reinstall will work out for the ol' HP