Apple Mac mini (Mid 2011) - Manual (Page 46)

46 Chapter 3 Boost Your Memory
Step 7: Reconnect the cables.
Reconnect the power cord and any other cables you disconnected.
Step 8: Check the new memory.
Press the power button to turn on your Mac mini.
When you see the Mac OS X desktop, choose Apple () > About This Mac and check
that the reported amount of memory is correct.
If the reported memory size isn’t correct, or if your Mac mini repeatedly sounds three
tones, it’s having trouble recognizing a memory module. If this happens, shut down
your Mac mini, verify the module specifications against the requirements listed on
page 41, and then repeat the memory installation instructions to make sure the modules
are installed correctly. If you still have problems, remove the memory and consult the
support information that came with the memory, or contact the vendor who provided
the memory.