IE launches but there’s no automation against the browser and the test fails. The failure log contains an error of this pattern:

[04/26 13:47:21,ArtOfTest.Runner.exe(146816:8),Framework] Connector.Start() : Process exited (ID=5560, ExitCode=0, Path="C:\Windows\SysWOW64\rundll32.exe", Arguments="ArtOfTest.Connector.dll,AttachToWindowEntryPoint 3212792").
[04/26 13:47:22,ArtOfTest.Runner.exe(146816:8),Error] TestExecuteProxy.ExecuteTest() : EXCEPTION! (see below)
     Outer Exception Type: System.ApplicationException
     Message: Exception thrown attempting to launch Internet Explorer. Please make sure Internet Explorer is properly installed and you are able to launch it.
     HRESULT: 0x80131600 (Official ID (if app.) = COR_E_APPLICATION, Error Bit = FAILED, Facility = FACILITY_URT, Code = 5632)
     Call Stack:
          at ArtOfTest.WebAii.BrowserSpecialized.InternetExplorer.InternetExplorerActions.LaunchNewBrowserInstance(Int32 timeout, ProcessWindowStyle windowStyle, String pipename)
          at ArtOfTest.WebAii.Core.Manager.LaunchNewBrowser(BrowserType browserToLaunch, Boolean waitForBrowserToConnect, ProcessWindowStyle windowStyle, String arguments)
          at ArtOfTest.WebAii.Design.Execution.ExecutionEngine.InitializeWeb(ExecutionEngineCreateParams initParams)
          at ArtOfTest.WebAii.Design.Execution.TestExecuteProxy.CreateAndInitializeEngine(Test test, ExecutionEngineCreateParams cp)
          at ArtOfTest.WebAii.Design.Execution.TestExecuteProxy.ExecuteTest(ExecuteTestCommand command)

     Inner Exception Type: System.ArgumentException
     Message: Process with an Id of 25720 is not running.
     HRESULT: 0x80070057 (Official ID (if app.) = E_INVALIDARG, Error Bit = FAILED, Facility = FACILITY_WIN32, Code = ERROR_INVALID_PARAMETER)
     Call Stack:
          at System.Diagnostics.Process.GetProcessById(Int32 processId, String machineName)
          at System.Diagnostics.Process.GetProcessById(Int32 processId)
          at ArtOfTest.Common.Extensions.ProcessExtensions.GetParentProcess(Process process)
          at ArtOfTest.WebAii.BrowserSpecialized.InternetExplorer.InternetExplorerActions.LaunchNewBrowserInstance(Int32 timeout, ProcessWindowStyle windowStyle, String pipename)

Workaround: Reboot the machine.