Packaging Error, Gauntlet.Automation.dll

I’m getting an error when I try to package a project. This has always worked fine for me in the past. It doesn’t seem like anything on my system has changed but something must have. I’ve done some googling but I don’t see anything related to this issue so I’m assuming that the cause is my system and not something with the engine or source (or it would be more widespread and show up in search results). Any help is much appreciated.

Steps to reproduce:

  1. Create a new project, version 4.24.3, c++, empty
  2. File->Package Project->Windows->Windows (64-bit)
  3. Select package folder

Expected result:
Project completes packaging

Actual result:
Packaging immediately errors with message below (from Log.txt)

Log.WriteException: ==============================================================================
Log.WriteException: ERROR: Failed to load script DLL: H:\Program Files\Epic Games\UE_4.24\Engine\Binaries\DotNET\AutomationScripts\Gauntlet.Automation.dll: Could not load file or assembly ‘Gauntlet.Automation.dll’ or one of its dependencies. An attempt was made to load a program with an incorrect format.
Log.WriteException: (see C:\Users\Cooper\AppData\Roaming\Unreal Engine\AutomationTool\Logs\H+Program+Files+Epic+Games+UE_4.24\Log.txt for full exception trace)
Log.WriteException:
Log.WriteException: AutomationException: Failed to load script DLL: H:\Program Files\Epic Games\UE_4.24\Engine\Binaries\DotNET\AutomationScripts\Gauntlet.Automation.dll: Could not load file or assembly ‘Gauntlet.Automation.dll’ or one of its dependencies. An attempt was made to load a program with an incorrect format.
Log.WriteException: at AutomationTool.ScriptCompiler.LoadPreCompiledScriptAssemblies(List1 OutScriptAssemblies) in D:\Build\++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\ScriptCompiler.cs:line 450 Log.WriteException: at AutomationTool.ScriptCompiler.FindAndCompileAllScripts(String ScriptsForProjectFileName, List1 AdditionalScriptsFolders) in D:\Build++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\AutomationUtils\ScriptCompiler.cs:line 74
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 477
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 176
Log.WriteException: at AutomationTool.Program.<>c__DisplayClass1_0.<Main>b__2() in D:\Build++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 88
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 731
Log.WriteException: at AutomationTool.Program.Main(String] Arguments) in D:\Build++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Programs\AutomationTool\Program.cs:line 88
Log.WriteException: ==============================================================================