The latest version of macOS X (10.13 - High Sierra) implements a new security feature which affects Snagit's ability to install and utilize the TechSmith System Audio Capture kernal extension, so that you will not be able to record system audio for the first time before doing the following steps.
This is a known issue that we are investigating with Apple. Users who have installed the system audio component from a TechSmith product prior to updating to macOS 10.13 will not be affected. Only new users who are installing the audio capture component for the first time on macOS 10.13 will be affected.
Steps to enable the extension
- Open Snagit and browse to the menu bar item Snagit > Preferences > Capture tab, and click the option to Install the System Audio component.
- Open System Preferences
- Open Security & Privacy
- Under the General tab, click Allow at the bottom
- Try recording system audio in Snagit. You may be asked to install the System audio component again. If so, follow the steps to install it again, and then give it another try.