Can´t boot MP from new cloned HD

[yoak]

Hi
I just installed 2 new HDs. I cloned my original disk (using Carbon) onto the new one and tried to boot up. I only get a grey screen, what have I done wrong?

 

[72930]

Try holding the option key at startup, see if it comes up, if so try selecting it. If not, insert your OSX disk and try doing an archive&install.

 

[yoak]

Thanks. I started up with my original HD and everything seems fine.I´ll give it one more try first

Edit: I opened a few apps from the new HD after booting from the original HD. Then restarted and chose the new HD. Worked like a dream this time