You are trying to install or open an app that didn't come from the Mac App Store but you got a message saying App can't be opened because it is from an unidentified developer. This is how you bypass it.
You created your own movie in iMovie but you can't figure it out how to save the darn thing into a playable .mp4 file on your hard drive. I've been there, let me show you how to do that.
Mac OS X Mountain Lion has 43 secret desktop wallpapers hidden in one of its folders. They are all beautiful, high quality and this is how you find them.
If you are more of a visual person and would like to organize your folders and files using different colors, than check it out how to use color labels in Mac OS X.
