1. Before you open your Mac Pro, shut it down by choosing Shut Down from the Apple () menu.
2. If the computer is warm to the touch, wait approximately 5-10 minutes for the computer to cool down.
3. Touch the metal enclosure on the outside of the Mac Pro to discharge any static electricity. 
   Important: Always discharge static before you touch parts or install components inside your Mac Pro. To avoid generating static, don't move around the room until you finish installing the memory and slide the enclosure back onto the computer.
4. Unplug all the cables and the power cord from your Mac Pro. Do not attempt to install memory while its plugged in.
5. Slide the enclosure latch to the right to unlock the enclosure.





6. Lift the enclosure straight up and off the computer and carefully set it aside.





7. The DIMM slots are now visible from the left and right side of the I/O panel.

Your Mac Pro shipped with DIMMs already installed in some or all of the DIMM slots. Before upgrading the memory, you may need to remove some or all of the DIMMs. Refer to the table below to determine how your Mac Pro is configured and to determine which DIMMs you need to remove and replace to maintain a recommended memory configuration. See the numbered steps following the table to locate specific DIMM slots.

Important: All DIMMs are 1866MHz DDR3 ECC. Do not mix UDIMMs and RDIMMs.

Remove DIMMs by following these steps.

1. There are a total of four DIMM slots, two are located to the left, and two are located to the right of the Mac Pro I/O panel. 
2. To access the DIMM slots, press the RAM bay release lever identified by a white triangle (A) located at the top of each DIMM bank. When pressed, the DIMM slots will swing out making them easily accessible.
3. Locate the DIMM(s) to be removed. The slots are number 1-4 (B). Using your thumb and index finger from each hand, gently grip the DIMM at each end and carefully remove the DIMM by pulling the DIMM straight out of the DIMM slot. Do not twist or force the DIMM out of the socket or damage may occur. Remove the outer DIMMs first to make the inner DIMMs easier to remove.





4. Place the removed DIMMs into an ESD (electrostatic discharge) protective bag.

Each DIMM (F) has a notch (E) that must line up with the key (D) inside of the DIMM slot (C). Note: The key/notch position is different on each side of the computer.

1. Locate the DIMM slot closest to the interior of the computer and confirm that no DIMM is there. 
2. If available, use canned air to blow dust and other contaminants out of the DIMM slot. Note: Keep the can vertical to avoid spraying propellants onto the DIMM slots.
3. Gently hold the DIMM ends and insert it into the slot. Ensure horizontal alignment of the DIMM prior to applying any force.
4. Insert the DIMM at the angle determined by the open DIMM mechanism.
5. Insert gently until bottom edge of DIMM is touching the gold contacts, then apply more force to fully seat the DIMM.
   • Do NOT force the DIMM. If the DIMM doesn't insert, verify that the key (D) and notch (E) are aligned.
   • Do NOT rock the DIMM into the seated position.
   • Do NOT insert DIMMs while the DIMM mechanism is in the locked position.
   • Do NOT bend or twist the DIMM during insertion.    
6. Press the RAM bay back into place after installing all DIMMs.

1. Carefully lower the enclosure over the Mac Pro being careful not to touch any of the circuit boards.
2. You may need to gently push down on the enclosure in order for it to seat fully.





3. Once the enclosure is fully seated, slide the enclosure latch to the left to lock it. 





4. If the enclosure latch does not move all of the way to the left, verify that the enclosure is properly installed and fully seated, then try again.
5. You are now ready to connect a power cord, display, and other peripherals. Power on your Mac Pro and verify that your system is operating properly.