Is this an engine packagine error?

Can’t for the life of me debug this myself.since it’s contained within the uobject globals files, I don’t really want to poke around and potentially scuff the whole project. Think it might be something to do with niagara?

Error txt

ProcessResult.StdOut:   LogOutputDevice: Warning:
ProcessResult.StdOut:   
ProcessResult.StdOut:   Script Stack (0 frames):
ProcessResult.StdOut:   
ProcessResult.StdOut:   LogWindows: Error: begin: stack for UAT
ProcessResult.StdOut:   LogWindows: Error: === Critical error: ===
ProcessResult.StdOut:   LogWindows: Error:
ProcessResult.StdOut:   LogWindows: Error: Fatal error: [File:D:\Build\++UE4\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectGlobals.cpp] [Line: 305]
ProcessResult.StdOut:   LogWindows: Error: Illegal call to StaticFindObject() while serializing object data!
ProcessResult.StdOut:   LogWindows: Error:
ProcessResult.StdOut:   LogWindows: Error:
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffb143ca388 KERNELBASE.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffaecc1cd1a UE4Editor-Core.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffaec9fa967 UE4Editor-Core.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffaec930df7 UE4Editor-Core.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffaec497111 UE4Editor-CoreUObject.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab5f6e0 UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab72750 UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab4a538 UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab585c4 UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab5d18f UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab616a2 UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab6131e UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab623f3 UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab610ca UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab5cd40 UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffadab721d7 UE4Editor-NiagaraShader.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffac8a9a963 UE4Editor-Niagara.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffac8a9a659 UE4Editor-Niagara.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffaec40fc3c UE4Editor-CoreUObject.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffae76b9206 UE4Editor-UnrealEd.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffae754ec97 UE4Editor-UnrealEd.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffae75514c1 UE4Editor-UnrealEd.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffae755cbe0 UE4Editor-UnrealEd.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffae73ba79b UE4Editor-UnrealEd.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffae73ed0bf UE4Editor-UnrealEd.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ff77b3fed22 UE4Editor-Cmd.exe!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ff77b3f5783 UE4Editor-Cmd.exe!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ff77b3f59ea UE4Editor-Cmd.exe!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ff77b4048da UE4Editor-Cmd.exe!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ff77b40584e UE4Editor-Cmd.exe!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffb175a3034 KERNEL32.DLL!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error: [Callstack] 0x00007ffb17983691 ntdll.dll!UnknownFunction []
ProcessResult.StdOut:   LogWindows: Error:
ProcessResult.StdOut:   LogWindows: Error: end: stack for UAT
CommandUtils.Run: Took 493.5792149s to run UE4Editor-Cmd.exe, ExitCode=3
InternalUtils.SafeDeleteFile: SafeDeleteFile C:\Users\Fearghall\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.21\Cook-2019.01.09-20.55.05.txt
InternalUtils.SafeCopyFile: SafeCopyFile C:\Program Files\Epic Games\UE_4.21\Engine\Programs\AutomationTool\Saved\Cook-2019.01.09-20.46.52.txt C:\Users\Fearghall\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.21\Cook-2019.01.09-20.55.05.txt
InternalUtils.SafeDeleteFile: SafeDeleteFile C:\Program Files\Epic Games\UE_4.21\Engine\Programs\AutomationTool\Saved\Cook-2019.01.09-20.46.52.txt
Log.WriteException: ==============================================================================
Log.WriteException: ERROR: Cook failed.
Log.WriteException:        (see C:\Users\Fearghall\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.21\Log.txt for full exception trace)
Log.WriteException: 
Log.WriteException: CommandletException: Editor terminated with exit code 3 while running Cook for C:\Users\Fearghall\Documents\Unreal Projects\Spellslinger_home\Spellslinger_home.uproject; see log C:\Users\Fearghall\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.21\Cook-2019.01.09-20.55.05.txt
Log.WriteException:    at AutomationTool.CommandUtils.RunCommandlet(FileReference ProjectName, String UE4Exe, String Commandlet, String Parameters, String& DestLogFile) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\CommandletUtils.cs:line 424
Log.WriteException:    at AutomationTool.CommandUtils.RunCommandlet(FileReference ProjectName, String UE4Exe, String Commandlet, String Parameters) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\CommandletUtils.cs:line 237
Log.WriteException:    at AutomationTool.CommandUtils.CookCommandlet(FileReference ProjectName, String UE4Exe, String[] Maps, String[] Dirs, String InternationalizationPreset, String[] CulturesToCook, String TargetPlatform, String Parameters) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\CommandletUtils.cs:line 89
Log.WriteException:    at Project.Cook(ProjectParams Params) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\CookCommand.Automation.cs:line 249Wrapped by AutomationException: Cook failed.
Log.WriteException:    at Project.Cook(ProjectParams Params) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\CookCommand.Automation.cs:line 263
Log.WriteException:    at BuildCookRun.DoBuildCookRun(ProjectParams Params) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\BuildCookRun.Automation.cs:line 209
Log.WriteException:    at BuildCookRun.ExecuteBuild() in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Scripts\BuildCookRun.Automation.cs:line 41
Log.WriteException:    at AutomationTool.BuildCommand.Execute() in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\BuildCommand.cs:line 242
Log.WriteException:    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
Log.WriteException:    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
Log.WriteException:    at AutomationTool.Program.MainProc(String[] Arguments, StartupTraceListener StartupListener) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 173
Log.WriteException:    at AutomationTool.Program.<>c__DisplayClass1_0.b__2() in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 99
Log.WriteException:    at AutomationTool.InternalUtils.RunSingleInstance(Func`1 Main) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\Utils.cs:line 725
Log.WriteException:    at AutomationTool.Program.Main() in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 99
Log.WriteException: ==============================================================================
Program.Main: AutomationTool exiting with ExitCode=25 (Error_UnknownCookFailure)

Full log:
link text
Cooking log:
link text

Hi

ProcessResult.StdOut: LogWindows: Error:
ProcessResult.StdOut: LogWindows: Error: Fatal error: [File:D:\Build++UE4\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectGlobals.cpp] [Line: 305]
ProcessResult.StdOut: LogWindows: Error: Illegal call to StaticFindObject() while serializing object data!

I do have exact same error on saving my project since a convert in place from 4.20 to 4.21

I am searching invalid object in my map since conversion to erase them.

Did you fix this?