Tried to upgrade from 10.7.4 on relatively new MBP. It appears that Mountain Lion successfully downloaded from App Store. However, ML will not install to the hard drive because "This disk cannot be used to startup your computer". Thanks for advice.
Hey JMN51 have you tried to repair the disk using recovery assistant
Try going through the steps described here: http://support.apple.com/kb/TS3926.
Thanks for the advice. Turns out that trying to install Mountain Lion uncovered a failing hard drive. It's being replaced.
Thanks. Turns out, the hard drive was malfunctioning. It is being replaced.
Retrieving data ...