"You cannot install "OS X" on this disk. OS X cannot start up from this disk."

gimlids said:

I have a triple boot situation, with reFIT and OS X Lion, Ubuntu, and Windows 7. Mid 2009 MBP. Whhhhhhhaaaaat do I do... besides nuking everything and starting from scratch...?

Click to expand...

I have no advice yet, but I am facing exactly the same problem. Will post back if I find the answer.

I think you have to delete the Macintosh HD first before it accepts it to install there by opening disk utility from the instalation menu

gimlids said:

I have a triple boot situation, with reFIT and OS X Lion, Ubuntu, and Windows 7. Mid 2009 MBP. Whhhhhhhaaaaat do I do... besides nuking everything and starting from scratch...?

Click to expand...

Nothing. Start from scratch. OS X does not support other boot loaders, but other boot loaders support OS X (and Windows, Linux, ...).

Same thing happen to me, but I tried again and it worked perfectly the second time.

Fixed

OK, I fixed it. What you need to do is to make sure you have a functioning Recovery Partition under Lion before you try the upgrade to Mountain Lion. Following these instructions worked for me. I didn't lose anything - not even my Ubuntu partition. Enjoying the Mountain Lion goodness!