TestComplete shows this message when you are trying to open the Mobile Screen window during the test run, but no mobile device is set as current in your test.
To resolve the issue, select the current device via the Select Local Device dialog before running your test, or add an operation to your test that will set the current device. In Keyword test, you can do this by using the Select Device operation. In script tests, you can do this by calling the MobileSetCurrent
method.
See Also
Mobile Screen Window
Select Local Device Dialog (Legacy Mobile Testing)