When attempting to set up a profiling session for a web application hosted in IIS, the following message may appear in the "Application Settings" window:

The Start Profiling button is disabled.

Before profiling, ANTS Profiler checks that the web address in the URL field has a valid structure. If the "path" is empty, ANTS Profiler shows this warning, preventing profiling.

If the URL to be profiled is the root web application, a "forward-slash" character must be specified as the application path.

For instance, the URL http://localhost is invalid. Changing this to http://localhost/ allows profiling to continue.