I might be experiencing something similar with GammaLauncher. When building from the editor (F10) it works just fine, but running from command line (using fallout in this case) errors with
[ERR] Compile: Unhandled exception. System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types.
[ERR] Compile: Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
[ERR] Compile: at System.Reflection.RuntimeModule.GetDefinedTypes()
[ERR] Compile: at System.Reflection.RuntimeModule.GetTypes()
[ERR] Compile: at VL.AppServices.CompilationHelper.SwapAssembly(Assembly assembly, Int32 pass)
[ERR] Compile: at VL.Model.VLSession.Swap(ITargetCompilation compilation)
[ERR] Compile: at VL.Model.VLSession.UpdateRuntimesAsync(PreCompilation preCompilation, CancellationToken token, IProgress`1 progress, Boolean incremental)
[ERR] Compile: at VL.Model.VLSession.UpdateCompilationCoreAsync(Solution solution, CompileOptions options, CancellationToken token, IProgress`1 progress, Boolean incremental)
[ERR] Compile: at Program.ConsoleSession.OnException(ExceptionDispatchInfo exceptionDispatchInfo)
[ERR] Compile: at VL.Core.AppHost.ReportException(ExceptionDispatchInfo exceptionDispatchInfo)
[ERR] Compile: at VL.Model.VLSession.UpdateCompilationCoreAsync(Solution solution, CompileOptions options, CancellationToken token, IProgress`1 progress, Boolean incremental)
[ERR] Compile: at VL.Model.VLSession.UpdateCompilationAsync(Solution solution, CompileOptions options, IProgress`1 progress, Boolean incremental, CancellationToken cancellationToken)
[ERR] Compile: at VL.Model.VLSession.UpdateAsync(Solution solution, SolutionUpdateKind kind, Canvas canvas, IProgress`1 progress, CancellationToken cancellationToken)
[ERR] Compile: at Program.ConsoleSession.OnException(ExceptionDispatchInfo exceptionDispatchInfo)
[ERR
] Compile: at VL.Core.AppHost.ReportException(ExceptionDispatchInfo exceptionDispatchInfo)
[ERR] Compile: at VL.Model.VLSession.UpdateAsync(Solution solution, SolutionUpdateKind kind, Canvas canvas, IProgress`1 progress, CancellationToken cancellationToken)
[ERR] Compile: at VL.Model.VLSession.AddRootAndLoadSymbolsAsync(Document document, CancellationToken token, IProgress`1 progress)
[ERR] Compile: at VL.Model.VLSession.LoadDocumentAsync(String filePath, CancellationToken token, IProgress`1 progress)
[ERR] Compile: at Program.<>c__DisplayClass0_0.<<Main>g__GenerateExecutableAsync|1>d.MoveNext()
[ERR] Compile: --- End of stack trace from previous location ---
[ERR] CompilePS D:\Documents\dev\apps\GammaLauncher\fallout\build> : at Program.Main(String[] args)
[ERR] Compile: at Program.<Main>(String[] args)
[ERR] Compile: System.IO.FileNotFoundException: Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
[ERR] Compile: File name: 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
Repro steps:
- Checkout the GammaLauncher repo at
c396d07115c5460fa65d120c8595f84d73cf42b6
- Open a PowerShell,
cd inside and run
& "C:\Program Files\vvvv\vvvv_gamma_8.0-0150-g64abc88e08-win-x64\vvvvc.exe" GammaLauncher.vl --output-type WinExe --rid win-x64 --clean
Here I’m getting
PS D:\Documents\dev\apps\GammaLauncher> & "C:\Program Files\vvvv\vvvv_gamma_8.0-0150-g64abc88e08-win-x64\vvvvc.exe" GammaLauncher.vl --output-type WinExe --rid win-x64 --clean
info: vvvv[0]
Loading GammaLauncher.vl
fail: vvvvc[0]
System.ArgumentException: The base path must be absolute. (Parameter 'basePath')
at VL.Lib.IO.Path.MakeAbsolute(Path basePath)
at VL.Model.Internal.Dependency..ctor(ObjectReader reader)
fail: vvvvc[0]
System.ArgumentException: The base path must be absolute. (Parameter 'basePath')
at VL.Lib.IO.Path.MakeAbsolute(Path basePath)
at VL.Model.Internal.Dependency..ctor(ObjectReader reader)
warn: packman[0]
There are 2 package sources defined in your configuration. When using central package management, please map your package sources with package source mapping (https://aka.ms/nuget-package-source-mapping) or specify a single package source. The following sources are defined: https://api.nuget.org/v3/index.json, https://teamcity.vvvv.org/guestAuth/app/nuget/feed/_Root/default/v3/index.json
info: packman[0]
Restoring packages for C:\Program Files\vvvv\vvvv_gamma_8.0-0150-g64abc88e08-win-x64\ROOT.proj...
info: packman[0]
CACHE https://api.nuget.org/v3/vulnerabilities/index.json
info: packman[0]
CACHE https://api.nuget.org/v3-vulnerabilities/2026.09.26.05.43.06/vulnerability.base.json
info: packman[0]
CACHE https://api.nuget.org/v3-vulnerabilities/2026.09.26.05.43.06/2026.09.30.05.43.24/vulnerability.update.json
info: packman[0]
Writing assets file to disk. Path: C:\Program Files\vvvv\vvvv_gamma_8.0-0150-g64abc88e08-win-x64\data\restore\ROOT\project.assets.json
warn: packman[0]
There are 2 package sources defined in your configuration. When using central package management, please map your package sources with package source mapping (https://aka.ms/nuget-package-source-mapping) or specify a single package source. The following sources are defined: https://api.nuget.org/v3/index.json, https://teamcity.vvvv.org/guestAuth/app/nuget/feed/_Root/default/v3/index.json
info: packman[0]
Restoring packages for C:\Program Files\vvvv\vvvv_gamma_8.0-0150-g64abc88e08-win-x64\ROOT.proj...
info: packman[0]
Writing assets file to disk. Path: C:\Program Files\vvvv\vvvv_gamma_8.0-0150-g64abc88e08-win-x64\data\restore\ROOT\project.assets.json
warn: packman[0]
Package version mismatch for VL.Core in project .\csharp\DeleteFolders.Utils\DeleteFolders.Utils.csproj. Referenced version: 2025.7.4, Resolved version: 2026.8.0-0150-g64abc88e08. This may lead to runtime errors.
fail: vvvv[0]
There are build errors.
crit: vvvv[0]
Unable to load one or more of the requested types.
Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types.
Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
at System.Reflection.RuntimeModule.GetDefinedTypes()
at System.Reflection.RuntimeModule.GetTypes()
at VL.AppServices.CompilationHelper.SwapAssembly(Assembly assembly, Int32 pass)
at VL.Model.VLSession.Swap(ITargetCompilation compilation)
at VL.Model.VLSession.UpdateRuntimesAsync(PreCompilation preCompilation, CancellationToken token, IProgress`1 progress, Boolean incremental)
at VL.Model.VLSession.UpdateCompilationCoreAsync(Solution solution, CompileOptions options, CancellationToken token, IProgress`1 progress, Boolean incremental)
System.IO.FileNotFoundException: Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
File name: 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
crit: vvvv[0]
Unable to load one or more of the requested types.
Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types.
Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
at System.Reflection.RuntimeModule.GetDefinedTypes()
at System.Reflection.RuntimeModule.GetTypes()
at VL.AppServices.CompilationHelper.SwapAssembly(Assembly assembly, Int32 pass)
at VL.Model.VLSession.Swap(ITargetCompilation compilation)
at VL.Model.VLSession.UpdateRuntimesAsync(PreCompilation preCompilation, CancellationToken token, IProgress`1 progress, Boolean incremental)
at VL.Model.VLSession.UpdateCompilationCoreAsync(Solution solution, CompileOptions options, CancellationToken token, IProgress`1 progress, Boolean incremental)
at Program.ConsoleSession.OnException(ExceptionDispatchInfo exceptionDispatchInfo)
at VL.Core.AppHost.ReportException(ExceptionDispatchInfo exceptionDispatchInfo)
at VL.Model.VLSession.UpdateCompilationCoreAsync(Solution solution, CompileOptions options, CancellationToken token, IProgress`1 progress, Boolean incremental)
at VL.Model.VLSession.UpdateCompilationAsync(Solution solution, CompileOptions options, IProgress`1 progress, Boolean incremental, CancellationToken cancellationToken)
at VL.Model.VLSession.UpdateAsync(Solution solution, SolutionUpdateKind kind, Canvas canvas, IProgress`1 progress, CancellationToken cancellationToken)
System.IO.FileNotFoundException: Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
File name: 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
Unhandled exception. System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types.
Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
at System.Reflection.RuntimeModule.GetDefinedTypes()
at System.Reflection.RuntimeModule.GetTypes()
at VL.AppServices.CompilationHelper.SwapAssembly(Assembly assembly, Int32 pass)
at VL.Model.VLSession.Swap(ITargetCompilation compilation)
at VL.Model.VLSession.UpdateRuntimesAsync(PreCompilation preCompilation, CancellationToken token, IProgress`1 progress, Boolean incremental)
at VL.Model.VLSession.UpdateCompilationCoreAsync(Solution solution, CompileOptions options, CancellationToken token, IProgress`1 progress, Boolean incremental)
at Program.ConsoleSession.OnException(ExceptionDispatchInfo exceptionDispatchInfo)
at VL.Core.AppHost.ReportException(ExceptionDispatchInfo exceptionDispatchInfo)
at VL.Model.VLSession.UpdateCompilationCoreAsync(Solution solution, CompileOptions options, CancellationToken token, IProgress`1 progress, Boolean incremental)
at VL.Model.VLSession.UpdateCompilationAsync(Solution solution, CompileOptions options, IProgress`1 progress, Boolean incremental, CancellationToken cancellationToken)
at VL.Model.VLSession.UpdateAsync(Solution solution, SolutionUpdateKind kind, Canvas canvas, IProgress`1 progress, CancellationToken cancellationToken)
at Program.ConsoleSession.OnException(ExceptionDispatchInfo exceptionDispatchInfo)
at VL.Core.AppHost.ReportException(ExceptionDispatchInfo exceptionDispatchInfo)
at VL.Model.VLSession.UpdateAsync(Solution solution, SolutionUpdateKind kind, Canvas canvas, IProgress`1 progress, CancellationToken cancellationToken)
at VL.Model.VLSession.AddRootAndLoadSymbolsAsync(Document document, CancellationToken token, IProgress`1 progress)
at VL.Model.VLSession.LoadDocumentAsync(String filePath, CancellationToken token, IProgress`1 progress)
at Program.<>c__DisplayClass0_0.<<Main>g__GenerateExecutableAsync|1>d.MoveNext()
--- End of stack trace from previous location ---
at Program.Main(String[] args)
at Program.<Main>(String[] args)
System.IO.FileNotFoundException: Could not load file or assembly 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
File name: 'System.Windows.Forms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'