Macbook Pro USB Port Not Working

I recently encounter a  problem with one of Macbook Pro usb port not working, the one which is closer to the battery side of the laptop. Doesn’t matter what devices I plugged into the slot, it won’t recognize it. This make it hard for me to copy files from one disk to another. I end up copying the files first onto my laptop, unplug the source disk for a destination disk and transferring the files back. This is not supposed to happen. At first I thought the port was somehow broken and was thinking to call Apple once I got back home but instead I looked for similar case in the internet for a solution.

What I gather from the Internet is that this is a problem with the port itself which is already connected to an internal USB hub that also feeds the keyboard, trackpad, iSight, Bluetooth, and IR receiver thus making it have not enough voltage to supply to another high-drained devices.

Then, I went on looking for a solution for this problem until I found a comment explaining how I can fix this problem by resetting SMC and PRAM. For those who had no idea of what this is, read more after the steps below.

SMC RESET

For Macbook, Macbook Pro with removable battery

• Shut down your Macbook.
• Unplug MagSafe power adapter from your Macbook.
• Remove the battery.
• Press and hold the power button for 5 seconds.
• Release the power button after 5 seconds.
• Insert the battery and plug in MagSafe power adapter.
• Power up your Macbook.

For Macbook, Macbook Pro without removable battery

• Make sure MagSafe power adapter is diconnected.
• Shut down the computer.
• Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
• On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
• Release all the keys and the power button at the same time.
• Press the power button to turn on the computer.

SMC (System Management Controller) is a chip on themotherboard. From the Wikipedia, it is written the System Management Controller (SMC) is an internal subsystem introduced by Apple Inc. with the introduction of their new Intel processor based machines in 2006. It is possible that the SMC could encounter an issue that may cause unusual system behavior and in some cases, resetting the SMC may be the only correct method to resolve the issue.

The other solution for ports issues on Macbook Pro and Air is to reset the PRAM (Parameter RAM). PRAM stores core information about your laptop thus if there are issues with how your laptop behave, resetting PRAM usually fixed it.

Here’s how to reset PRAM/NVRAM.

• Shut down your laptop.
• Press the combination of Power + Cmd + Option + P + R keys.
• While still holding the key combination above, turn on your laptop (make sure you pressed these keys before the gray screen comes up).
• Keep holding the keys until your laptop reboots and you hear the startup chime.
• Release the key and restart the laptop again normally.

[UPDATE]

I found out that many people upgraded their Snow Leopard to Lion has this problem with battery drain too fast so I am happy to say this SMC Reset is also one of the solution to that problem.