Well, apparently you can't swap hard drives any more in Macs ...

So, I guess I've been out of the loop for a while.

It appears that starting with Snow Leopard (maybe sooner) you cannot take a hard drive out of one Mac and put it in another one.

It won't boot ~ even if you used it externally to boot your Mac.

You get the folder with a question mark on it.

It seems the MacOS now ties hard drive serial numbers to the motherboard.

So, with each new installation of a hard drive … you have to install a fresh (authorized) copy of Mac OS X then do a migration of all your files.

Boo.