For enough clearance to remove the hard drive, the logic board must be slightly removed. To accomplish this, two cylindrical rods must be inserted into the holes highlighted in red.

Inserting instruments into any logic board holes other than the ones highlighted in red may severely damage the logic board.

Insert a Mac mini Logic Board Removal Tool into the two holes highlighted in red. Be sure it makes contact with the outer case below the logic board before proceeding.

If you don't have a Logic Board Removal Tool handy, you can use two tools having a maximum diameter of 2.5 mm instead. Just insert one into each of the highlighted holes.

Carefully pull the tool toward the I/O board. The logic board and I/O board assembly should slightly slide out of the outer case.

Cease prying when the I/O board is visibly separated from the outer case. Remove the Mac mini Logic Board Removal tool.