During the build, the output is displayed in the Application Build output pane. This is a normal editor text box which you can search and edit in the usual way.
If there is an error during the build, a backtrace is generated and the subprocess image exits.
To view the error message choose Build > Display Error or click the toolbar button.
To view the error message and the backtrace in an Editor tool choose Build > Display Backtrace or click the toolbar button. Most errors can be resolved after checking the backtrace.
To clear the Application Build output pane choose Build > Clear Output or click the toolbar button.
You can set the tool to do this automatically - for the details see 28.9 Configuring the Application Builder.
LispWorks IDE User Guide (Macintosh version) - 01 Dec 2021 19:36:40