Error: Launch failed! Unknown Error

Hi everyone,

When i try to launch my game in the editor, it fails. I can’t really figure out what the problem is. Can someone help me with this error?

Here you have the output log:

LogPlayLevel: WARNING: Win64 does not implement Deploy…
LogPlayLevel: ********** DEPLOY COMMAND COMPLETED **********
LogPlayLevel: ********** RUN COMMAND STARTED **********
LogPlayLevel: Starting Client…
LogPlayLevel: ERROR: System.ArgumentOutOfRangeException: The index is out of range. It can not be negative and must be smaller than the size of the collection.
LogPlayLevel: Parameternaam: index
LogPlayLevel: by System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
LogPlayLevel: by System.Collections.Generic.List1.get_Item(Int32 index) LogPlayLevel: by Project.SetupClientParams(List1 DeployContextList, ProjectParams Params, String ClientLogFile, ERunOptions& ClientRunFlags, String& ClientApp, String& ClientCmdLine) in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\RunProjectCommand.Automation.cs:line 633
LogPlayLevel: by Project.RunInternal(ProjectParams Params, String ServerLogFile, String ClientLogFile) in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\RunProjectCommand.Automation.cs:line 173
LogPlayLevel: by Project.Run(ProjectParams Params) in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\RunProjectCommand.Automation.cs:line 115
LogPlayLevel: by BuildCookRun.DoBuildCookRun(ProjectParams Params) in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\BuildCookRun.Automation.cs:line 224
LogPlayLevel: by BuildCookRun.ExecuteBuild() in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\BuildCookRun.Automation.cs:line 41
LogPlayLevel: by AutomationTool.BuildCommand.Execute() in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\BuildCommand.cs:line 112
LogPlayLevel: by AutomationTool.Automation.Execute(List1 CommandsToExecute, Dictionary2 Commands) in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\Automation.cs:line 562
LogPlayLevel: by AutomationTool.Automation.Process(String] Arguments, StartupTraceListener StartupListener) in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\Automation.cs:line 532
LogPlayLevel: by AutomationTool.Program.MainProc(String] Arguments, StartupTraceListener StartupListener) in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 174
LogPlayLevel: by AutomationTool.Program.<>c__DisplayClass1_0.<Main>b__0() in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 100
LogPlayLevel: by AutomationTool.InternalUtils.RunSingleInstance(Func`1 Main) in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\Utils.cs:line 725
LogPlayLevel: by AutomationTool.Program.Main() in D:\Build++UE4\Sync\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 100
LogPlayLevel: (see C:\Users\icali\AppData\Roaming\Unreal Engine\AutomationTool\Logs\E+Unreal+Project+Engine+UE_4.20\Log.txt for full exception trace)
LogPlayLevel: AutomationTool exiting with ExitCode=1 (Error_Unknown)
LogPlayLevel: Completed Launch On Stage: Deploy Task, Time: 0.250851
LogPlayLevel: Completed Launch On Stage: Run Task, Time: 0.000048
LogPlayLevel: BUILD FAILED
PackagingResults: Error: Launch failed! Unknown Error

I’m getting the same error.

Same error. I can’t launch anything. Tried 3 different templates. My error message looks exactly the same as yours though.

Same here.

Same here.

same here…found no solution
here anybody they found a fix ???

Support ???