I’ve read a few articles at different tech sites, along with some Apple support forum postings, discussing a problem with keyboard and trackpad issues on new MacBook Pro Retina systems. Apple even has a support article titled MacBook Pro (Retina, 13-inch, Late 2013): Keyboard and Multi-Touch trackpad may become unresponsive.
I don’t think this issue is limited only to newer MacBook Pro Retina systems. A day after upgrading my wife’s 13″ MacBook Pro, which is a 2010 or 2011 model (and doesn’t have a Retina Display), we experienced a similar problem. She was trying to use her laptop but the mouse cursor did not follow the movements on the trackpad. It seemed to stop responding for brief moments and then move off in a slightly different direction when it did work. I witnessed this problem myself and even checked to see if something had gotten on the trackpad that was throwing it off. Nothing had.
Because I had yet to learn of this problem I happened on the solution by accident. My wife had become frustrated so she closed her laptop and let it sleep. I grabbed it, opened the display, but it wouldn’t fully wake up (an issue that itself isn’t exactly rare). Rather than power the laptop off, not knowing what she may have left open and unsaved, I simply closed the lid and waited until the LED pulsed to indicate that the system was sleeping. Then I opened it back up. This time the system woke up properly and, once again, the trackpad behaved normally.
It’s certainly possible that something else was the cause but the problem hasn’t recurred so I doubt it’s a hardware issue. This has never happened before. In addition, a friend of mine mentioned that he also had a similar problem with an older MacBook Pro. So, if you have an older MacBook Pro that behaves this way try the solution for new MacBook Pro systems.