I am about to replace my 500GB HDD with a 2T HDD. In reviewing any possible problems I might in counter, I have seen where in 2011 there was an issue with the HDD fan control software. Some individuals used a third party software to control the fan but that lead to the machine not passing the AHT used by apple. My unit is not under warranty therefore can't see taking it to them at this point anyway. My question - Has this issue been fixed, with the numerous upgrades of the OS since 2011? I am now running OS X Yosemite 10.10.4. If not fixed through the OS would it be a non-issue since I cloned my HDD instead of just reinstalling the OS from the application disks? If the cloning does not add the needed firmware are there trustworthy third party software out there that will control my HDD fan?