"Exceptions" telemetry shows exceptions which were thrown in the profiled application.
Exceptions may be grouped by their exception class or by thread in which they occurred. Selecting an exception in the upper table allows viewing the exception stack traces.
Checkbox "Show exceptions thrown and caught inside filtered methods" enables to filter out exceptions which have been thrown and caught in methods of library classes. By default, the checkbox is unselected, as such kind of exceptions are usually of no interest when profiling your application.
The exception telemetry is always available, as it adds no overhead.
You can clear recorded exceptions with the help of corresponding toolbar button:
You can compare exception statistics of two snapshots with the help of "File | Compare Snapshot with...".