Fix NotFoundError in .NET

.NET NotFoundError and Assembly Loading Issues

The FileNotFoundException: Could not load file or assembly error in .NET indicates a missing DLL, version mismatch, or platform-specific assembly issue.

NuGet Restore

The simplest fix — dependencies weren't restored:

dotnet restore
dotnet build

Version Mismatch

Package A requires version 2.0 of a library, but Package B pulled in version 3.0:

<!-- .csproj — pin the version -->
<PackageReference Include="Newtonsoft.Json" Version="13.0.3" />

Platform-Specific Assemblies

Native libraries need the correct runtime identifier:

# Publish for specific platform
dotnet publish -r linux-x64 -c Release
dotnet publish -r win-x64 -c Release
dotnet publish -r osx-arm64 -c Release

Binding Redirects (.NET Framework)

<!-- app.config / web.config -->
<dependentAssembly>
  <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" />
  <bindingRedirect oldVersion="0.0.0.0-13.0.0.0" newVersion="13.0.0.0" />
</dependentAssembly>

Fusion Log for Debugging

Enable fusion logging to see exactly where .NET looks for assemblies:

# .NET Core
set COREHOST_TRACE=1
dotnet run

Self-Contained Deployment

For guaranteed dependency resolution:

dotnet publish -c Release --self-contained true -r linux-x64

Bugsly captures assembly loading failures with the expected version, attempted paths, and calling assembly — critical information for diagnosing deployment issues.