Many of us who use the computer regularly, and consider ourselves 'moderate-to-hardcore' software junkies, know that after using your computer for any extended amount of time, the OS often times becomes mugged up with lots of orphaned files, preference files that are no longer in use, background processes for software that you could have sworn you'd completely deleted over a year ago, etc, etc... Performing a complete clean installation of your Mac OS is a surefire way to get things running as smoothly as the day you bought your computer. Something that is often overlooked when performing clean installations is the fact that there are a number of applications that actually require being "Deauthorized" prior to uninstalling them. Failure to remember to do so might mean that you will have to purchase a brand new license for the software in order to be able to use it again (or at the very least will require a lengthy phone call to the customer support division of the software developer to see if they can help) I feel that compiling a list of all applications that need to be formally "Deauthorized" would be a tremendous asset to the Mac community, and so, I would very much like to start one such list right here and now! Apps requiring "Deauthorization" prior to being uninstalled (or prior to a clean install of your OS): iTunes Adobe Creative Suite (as well as most individual 'Creative Suite' apps, such as Photoshop CS4 standalone) iSale Flip4Mac WMV Studio Pro HD You Control Mark/Space Missing Sync Software (?) BIAS Peak Pro Spore Please chime in with any other apps you can think of that should be tacked onto this list! **and for the sake of having a relatively clutter-free thread used for reference purposes only, please don't chime in with any comments about any technical details about anything that's been said. Let's try to keep this thread clean, concise, and to the point. Thanks!