What to do when OS X Recovery Partition won’t boot

Problem 

Today, while I was working on my Mac, I dropped a couple of books from my desk on the power chord (I use a surge suppressor), which caused it to die.

As usual, I unplugged the power chord for a while and then pressed down the power button for about 30 seconds to discharge any remainder statics.

Then re-plugged the power chord and restarted my Mac.

I wanted to repair any errors caused by this unexpected event, so I booted from Recovery Partition for accessing Disk Utility.

But, this time, a surprise was waiting for me.

OS X got stuck and a stop signal was suddenly shown.

I totally freaked out for a second, knowing that symbol can only mean bad news, then OS X keeps going and boots to my desktop.

Pheeeeew!

What the heck?

My initial guess was I had messed up my recovery partition, so I fired the diskutil list command in the Terminal.

Luckily, though, the output looked good, as my recovery partition was still there.

So I rebooted my Mac, to rule out a temporary failure, but I got the same output as above.

Solution

After investigating online, I found the problem can be solved in different ways:

1. Resetting PRAM/NVRAM: This is done by pressing simultaneously CMD+ALT+P+R at boot-up. If the operation is successful, the Mac will restart automatically.
2. Repairing the disk: You can use the Install DVD (available only for Snow Leopard and earlier versions), or third party utilities such as Disk Warrior.
3. Reinstalling OS X: You can use a Time Machine Backup, a clone realized with Super Duper! or Carbon Copy Cloner, or an emergency USB Installer. In all these cases, don't erase your current partition. We only want to reinstall the operating system, so it can boot from Recovery Partition again.

I tried the first solution and, thankfully, it worked, but I had a hectic half an hour in an otherwise dull afternoon.