Chosen Solution
My MacBook Pro is stuck with a prohibited sign when it’s starting up.
Here’s a good Apple T/N that describes what it means: About the screens you see when your Mac starts up Depending on what your systems firmware is you should be able to do an internet recovery to restore your OS, if not you’ll need to find a friend to either help you create a bootable OS installer or leverage his system in target mode to fix yours. Here’s an Apple T/N on how do both: Startup key combinations for Mac At worse your HD and/or HD SATA cable is bad which is a common issue in this series (what is the most likely here).
