This was originally found with Android Launch On but also occurs Launching on to Windows with a new project.
This will not reproduce when using a build from Perforce
ogPlayLevel: Setting up ProjectParams for E:\Unreal Projects\421_Binary\MRTest_BPm\MRTest_BPm.uproject LogPlayLevel: ********** STAGE COMMAND STARTED ********** LogPlayLevel: Error: ERROR: Stage Failed. Missing receipt 'E:\Unreal Projects\421_Binary\MRTest_BPm\Binaries\Win64\MRTest_BPm.target'. Check that this target has been built. LogPlayLevel: (see C:\Users\john.mauney\AppData\Roaming\Unreal Engine\AutomationTool\Logs\E+Program+Files+UE_4.21\Log.txt for full exception trace) LogPlayLevel: AutomationTool exiting with ExitCode=103 (Error_MissingExecutable) LogPlayLevel: Completed Launch On Stage: Build Task, Time: 1.256872 LogPlayLevel: Completed Launch On Stage: Deploy Task, Time: 0.000144 LogPlayLevel: BUILD FAILED PackagingResults: Error: Launch failed! Missing UE4Game binary. You may have to build the UE4 project with your IDE. Alternatively, build using UnrealBuildTool with the commandline: UE4Game <Platform> <Configuration>
The issue requires using a Binary build to reproduce
RESULT:
ERROR: Stage Failed. Missing receipt 'E:\Unreal Projects\421_Binary\MRTest_BPm\Binaries\Win64\MRTest_BPm.target'. Check that this target has been built.
AutomationException: Stage Failed. Missing receipt 'E:\Unreal Projects\421_Binary\MRTest_BPm\Binaries\Win64\MRTest_BPm.target'. Check that this target has been built. at Project.CreateDeploymentContext(ProjectParams Params, Boolean InDedicatedServer, Boolean DoCleanStage) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\CopyBuildToStagingDirectory.Automation.cs:line 2728 at Project.CopyBuildToStagingDirectory(ProjectParams Params) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\CopyBuildToStagingDirectory.Automation.cs:line 2795 at BuildCookRun.DoBuildCookRun(ProjectParams Params) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\BuildCookRun.Automation.cs:line 219 at BuildCookRun.ExecuteBuild() in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\BuildCookRun.Automation.cs:line 41 at AutomationTool.BuildCommand.Execute() in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\BuildCommand.cs:line 242 at AutomationTool.Automation.Execute(List`1 CommandsToExecute, Dictionary`2 Commands) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\Automation.cs:line 563 at AutomationTool.Automation.Process(String[] Arguments, StartupTraceListener StartupListener) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\Automation.cs:line 533 at AutomationTool.Program.MainProc(String[] Arguments, StartupTraceListener StartupListener) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 173 at AutomationTool.Program.<>c__DisplayClass1_0.<Main>b__2() in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 99 at AutomationTool.InternalUtils.RunSingleInstance(Func`1 Main) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\Utils.cs:line 725 at AutomationTool.Program.Main() in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 99
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-65430 in the post.