Customer has a Silverlight application. The login page is using a hyperlink for the login. When you playback a fresh recording of the login sequence it errors out with:
System.TimeoutException: Wait for condition has timed out
   at ArtOfTest.Common.WaitSync.CheckResult(WaitSync wait, String extraExceptionInfo, Object target)
   at ArtOfTest.Common.WaitSync.For[T](Predicate`1 predicate, T target, Boolean invertCondition, Int32 timeout, WaitResultType errorResultType)
   at ArtOfTest.Common.WaitSync.For[T](Predicate`1 predicate, T target, Boolean invertCondition, Int32 timeout)
   at ArtOfTest.WebAii.Silverlight.VisualWait.ForVisible(Int32 timeout)
   at ArtOfTest.WebAii.Silverlight.VisualWait.ForNoMotion(Int32 initialWait, Int32 motionCheckInterval, Int32 timeout)
   at ArtOfTest.WebAii.Design.Execution.ExecutionUtils.WaitForNoMotionIfNeeded(AutomationDescriptor descriptor, Int32 timeout)
   at ArtOfTest.WebAii.Design.Execution.ExecutionUtils.WaitForAllElements(IAutomationHost host, AutomationDescriptor descriptor, Int32 timeout)
   at ArtOfTest.WebAii.Design.Execution.ExecutionEngine.ExecuteStep(Int32 order)

Test Studio records a click on the TextBlock element contained in the hyperlink, which may be part of the problem. A HyperLink element actually has 2 TextBlock elements contained under it. 1 is visible and the other is not. If Test Studio is finding the incorrect one this may be the cause of this problem.

Customer is using a workaround of finding the parent HyperLink element in the visual tree and having Test Studio click on it instead. It's a cumbersom work around, but usable. This workaround shouldn't be necessary however.