Mountain Lion Failed to Install

I have a MacBook Pro purchased in early 2011. It has Snow Leopard 10.6.8, 4GB RAM, and a 2.53GHz i5 processor. I downloaded Mountain Lion from the Apple Store, tried to install it, and failed.

It spent about 2 minutes "preparing" for the install, then told me it was going to auto-restart at the end of a countdown. When the countdown finished, it did not restart. Instead, I got the message that the installation had failed.

In prep for the install, I created a Mountain Lion Boot USB, made a clone of my current OS and hard drive, did a Time Machine backup, Verified the hard drive and verified/repaired permissions.

What am I missing, and what should I do next to get this to work? If the answer is "clean install," then how do I do that? Thanks for your help!

G'day and welcome to the forums.

You need to have Mountain Lion on the USB thumb drive prior to running the Installer. Is this what you did? If not you can go ba k into the App Store, hold down Option and hit Purchases, select Mountain Lion and download again - I know big download. Then download Lion Discmaker and follow directions prior to installing.


http://blog.gete.net/lion-diskmaker-us/

Thanks! That was where I made my error--tried to install it directly from the main HD. Mountain Lion is now up and running in fine fashion!

Good work. Keep coming back lots to love here3.