By default, this parameter is set to 90 seconds. This implies that the simulator will wait for a maximum of 90 seconds (by default) for an application/desktop to launch. If the application/desktop does not launch even after the 90 seconds have elapsed, then the simulation will be automatically terminated, and the simulator will mark that application/desktop launch as 'failed'. Accordingly, the Application launch availability measure for that published resource (i.e., application/desktop) will report the value 0, and no launch duration will be reported for the same.
In some environments, one/more published applications may take a little longer to launch than the rest. In such environments, you can instruct the simulator to wait longer for launching each of the configured published resources, by increasing the launch timeout. The high time out setting for resource launch ensures that the simulator captures and reports only genuine launch failures, and does not treat a launch delay as a failure.