"Although this article may be a little 'nerdy' for some," begins Jim Hamm, "I found it quite interesting in explaining the difference between the Registry in Windows and .plist files in OS X.

"The author uses an analogy of thinking of the Registry as a skyscraper, with each program built on top of another. If one program, or 'floor', if you will, should fail it may bring the entire skyscraper down. Plist files (lists of programs) in OS X, on the other hand, are built kinda side by side. If one fails, it's not likely to affect the other programs.

"Interesting analogy the author used, I thought, and helped me understand the differences between the two methods," Jim comments.

Here John Carter adds his thoughts to the situation, "Apple maintains .plist files in two places. One is in ~/Library/Preferences and the other is in /Library/Preferences. Notice that the '~' represents your home folder (/Users/).

Now, John goes into details. "Apple's .plist structure does two things. It determines how an application will run on your computer and one of them will contain registration information, if needed. You can delete ALL the .plist files on your computer and the core system will still work. What you have mostly done is to remove the system and user preferences for how things work - and also the registration information for apps that you purchased, which means you would have to re-register those apps.

"Using AppCleaner will successfully remove all .plist files for a given app from the computer and thereby allowing you to re-install the app from scratch if that's what you need to do to make a failing app work again."

And here John concludes his explanation, "One trick that IT professionals use to isolate the cause of a failing app is to rename ~/Library/Preferences or move it to another location. That folder and its content will get recreated when any of the apps storing a .plist file are run again. If the problem goes away, it's just a matter of singling out which .plist file in the original folder caused the problem.

"The other trick is to create a new user, login as that new user, and run the app. If the problem persists, then it might be a system related problem which might be found in /Library/Preferences, but it's best to reinstall the app from scratch before messing around with system files."