Last night I upgraded th HDD in my 2009 15" Unibody. I put the drive in an external enclosure and used Carbon Copy Cloner beforehand, cloned the drive, etc. and all went well. Afterwords I replaced the drive and booted up. Immediatly problems popped up, finder timed out a few times, and other oddities forced me to hard reboot a few times. I assumed something may have gone wrong with the clone so put in my Snow Lep CD and tried to do a clean install on the drive Wichita crashed on me three times. Frustrated I plugged my old drive into the USB and booted into it hoping to try CCC again, however the 1 TB seems to have problems remaining mounted when it is in the internal bay. Tried it a few times, the drive will mount on boot and I can access it for a bit before it randomly dismounts on me. Everything seemed fine before the install, this morning I was planning on swapping them out and trying C C C again, running Tech Tools Pro, etc. Just wondering though if anyone might know what's going on? Is the drive likely defective? Is the SATA connector loose? Not enough power to run it properly internally? Will post the exact drive in a moment.