If you've installed Apple's Mavericks on your Mac, you may have noticed that TextExpander won't work right away. That's because you've got tell the OS that TextExpander has permission to control your Mac. However, the process isn't clear. Fortunately for you I've figured it out. Here's how to get TextExpander working with Mavericks.
When you first launch TextExpander after installing Mavericks (or click its icon if you've set it to launch automatically after a reboot), you'll see a dialog box like this (and yes, I have a snippet that spells "Dalrymple" for me):
The box notes that you must open the "Universal Access" system