TestComplete shows this message when you are trying to modify the Count property of a test item that is configured to be rerun if it fails.
You cannot modify the Count property of such a test item; it is always set to 1. During the testing session, the test item will run once. If it fails, it will be rerun until it passes or until the maximum rerun number is reached. You can set the maximum rerun number on the Properties > Playback page of your project.
To learn more, see Controlling Test Execution Flow.
See Also
Tests, Test Items, and Test Cases
Execution Plan Editor
Stop and Rerun the Current Test Item After an Error