If you get this error, your keyword-driven test does not include a Start application keyword as the first keyword. Silk Test Workbench requires the Start application keyword to apply the application configuration of your project to the keyword-driven test. When you record a new keyword-driven test, Silk Test Workbench automatically adds the Start application keyword as the first keyword to the keyword-driven test.
With Silk Test Workbench 19.5 or later, parallel testing is enabled by default. When you upgrade from a Silk Test Workbench version prior to Silk Test Workbench 19.5 to a more recent Silk Test Workbench version, previously executing keyword-driven tests might no longer execute because each individual test is now expected to specify the application under test (AUT).
To workaround this issue, disable parallel testing on the machine on which Silk Test Workbench is running by setting the environment variable SILKTEST_ENABLE_PARALLEL_TESTING to false.
When replaying multiple keyword-driven tests from Silk Central with Silk Test Workbench 19.5 or later, parallel testing is enabled by default. When you upgrade from a Silk Test Workbench version prior to Silk Test Workbench 19.5 to a more recent Silk Test Workbench version, Silk Test Workbench will by default close the browser or the mobile app whenever a keyword-driven test is finished.
This issue does not occur when testing a browser application against Internet Explorer. To workaround this issue, disable parallel testing on the machine on which Silk Test Workbench is running by setting the environment variable SILKTEST_ENABLE_PARALLEL_TESTING to false.