Logout has timed out because application

I currently have 2 iMac's running 10.5.7 with the exact same hardware.

The problem that I keep experiencing is that I get the following error message when trying to log out.

"Logout has timed out because the application <app name> failed to quit. to try again, quite <app name> and choose Log Out from the Apple menu.

You can use the Force Quit menu item in the Apple menu (or press Command+Option+Esc) to quit an unresponsive application".

First I will say, that both iMacs are experiencing this intermittent problem. This usually occurs after an 8 hour day on the systems (leads me to believe there's a run away processes).

Secondly, the application it states that it failed to quit is not running. For instance, it will state Safari failed to quit, but Safari is only in my dock and not running. I've checked to see in the Activity Monitor if it shows that it's running, but it is not. Even going so far as using Force Quit with nothing listed.

I'm quite frustrated by this and Apple's support has no clue outside of unplugging everything and holding down the keys to do a reset. That's not a solution. I've even gone so far as to check my permissions and disks and even that has not fixed this issue.

The only computer that has the same OS and not experiencing this problem is our old Mac mini. I do not know if this is a hardware or software issue.

Let me know if anyone else has experienced this and has a possible solution.

Thanks

Are you actually closing the application before logging out? Hitting the little red button only closes the window and not the application at times and you need to use the menu bar quit application to get out.

Does the little indicator stay on under the Safari icon in the Dock?

Yes, the application is fully closed and not running. I've gone so far as to remove those apps from my dock. The only thing in my dock is Finder, Widgets, Trash and System Preferences.

I'm surprised that no one else has experienced this before.

Only other question is the Leopard install DVD the black full retail version?

Check "activity Monitor" app just before shutdown to make sure all app processes are quit and not there anymore. That is a good place to see if there is a hidden process causing this.

Both iMacs are only 1 month old and they came pre-installed with Leopard. I am not about to re-install Leopard on both of my iMacs as that's not a solution.

Secondly, I have looked that the activity Monitor several times as mentioned above and there are no app process running outside of Activity monitor.

Let me know if anyone has further feedback.

The machines that are having the problem, are they by chance networked together or part of a home network?

Regards.

They are all a part of a home network. Each connects via Airport to the home network.

All other systems such as mac mini and other pc's have no issues in shutting down a mentioned before.

Just wireless only? Or do you have file sharing turned on? If you do, as a test, remove the two iMac machines from the network, or one at a time and see if they shutdown properly. If the problem goes away, something (perhaps sharing) is keeping the application(s) open - not necessarily on each individual machine. In any event, that will give you a place to start looking.

Regards.