The 2012 Mac mini is a great machine, but we have found one small issue with it. Some units may not have proper shielding applied internally on the Bluetooth module and thus can experience interference from USB 3.0 drives.
This situation appears to be due to the specific placement of shielding which can vary from unit to unit. As a result, some mini users may experience diminished and/or up to total loss of Bluetooth use even at very short range.
The OWC Bluetooth Shielding Kit is a simple, DIY solution that substantially improves Bluetooth range. It comes complete with all tools, instructions, and a special EMI shielding foil with non-conductive adhesive. After installing this kit, you should experience improved functional Bluetooth range up to 20 feet.
For full details about the Mac mini 2012 Bluetooth issues please read our blog post.