I have an Intel iMac. I've noticed that many Apple apps (iTunes, iMovie, iPhoto, etc.) will often report that there is a new version available and ask if I want to download and install the update. On occasion, there is an update, but 90% of the time that I say yes, Software Update will open, check for updates, and report that there are "No new software updates". What is going on here? Why does an app report there is an update when Software Update says there is none? Is there any way to fix this?