The answer is no. Please see step 7 here. There is only 15mm of "extra space" underneath the factory original 9.5mm drive. Actually for a number of reasons should not attempt to put 1 in there with a standard 9.5mm drive. Read the reviews here on the Seagate Constellation.2 ST91000640NS hard drive. It is a power hog the Mini's power supply more than likely couldn't power it up and if it did you would suffer other consequences in the USB realm and others. It runs very hot, not a good thing in the mini. If you got to have internal Terra drives go with the newer WD Scorpio Blue Or the Samsung for inside the Mini.

Personally with a Mini. I would go with a SSD for my operating system, virtual memory and programs.Then a larger slower hard drive for data. It is actually the hard drive that the virtual memory is placed on that makes the biggest difference in a computers performance. After that, it is the hard drive the operating system is on that determines how snappy a computer performs. Your data hard drive doesn't need to be fast. It needs to be reliable.

As far as i know two drives 9.5 mm is your current option, and a "fast" 1TB drive in that size isn't around yet as far as i know.

Western Digital makes a 1TB blue line that should work fine.

You would have to go a bit smaller 500-750GB WD's black line for a proper fit and a higher performance drive, Black line also has advanced format models, 4k sectors, allowing for more useable space after formatting then a regular drive........and a 5yr warranty........Black line drives are quick .......some people have claimed to get a 12.5 to work with some "modification" however you risk damaging the computer.

Hatachi makes some nice drives too........ i am most familiar with WD's line as i have been using them for years.

hope this helps.

I tried installing a 1.5Tb 15mm Seagate FreePlay in my 2011 MacMini to use as a data drive but it's just a hair bit too thick for comfort, so I ended up putting in a Toshiba 12.5mm 1Tb drive and yes that extra 2.5mm does make a difference.

I have successfully installed the 12.5 mm WD Scorpio Blue (1TB) in the upper bay. I do not have a heat issue, especially after replacing the heat sink interface with Arctic Silver 5 Thermal paste. Its snug, but it slipped in easily. I agree with ABCellars with regards to the SSD as the boot drive. The WD is only 5200 rpms but it is plenty fast for a storage drive. Power consumption is well within the capabilities of the power supply, so I wouldn't worry about that.

I was able to add 2 TB WD 15 mm drive underneath sandisk ssd 480 gb drive. SSD is the boot drive

mdgrmg - Any heat issues experienced? I am about to go with the 15mm WD 2TB and a Samsung 840 Pro 7mm