dotnet/efcore · error · InvalidOperationException

Metadata model returned should not be 'null'. Provider

Error message

Metadata model returned should not be 'null'. Provider: {providerTypeName}.

What it means

Thrown after the database provider's IScaffoldingModelFactory.Create() returns null when converting the reverse-engineered DatabaseModel into an EF IModel. EF Core requires a non-null model from the provider; a null return signals an internal provider defect, not a user modeling problem. The message names the offending factory type to localize the bug.

Solutions

Update the database provider package (e.g. Microsoft.EntityFrameworkCore.SqlServer, Pomelo, Npgsql) to the version matching your EFCore.Design/EFCore version.
If using a custom or preview provider, inspect its IScaffoldingModelFactory implementation for a code path that returns null.
Open an issue with the provider project, including the factory type name from the message and the database schema that triggered it.
As a workaround, scaffold against SQL Server/SQLite/localdb to validate the rest of the pipeline, then swap providers.

Example fix

// before: mismatched versions
//   EFCore.Design 8.0.x  +  provider 7.0.x
// after: align patch versions
//   dotnet add package Microsoft.EntityFrameworkCore.SqlServer --version 8.0.x
//   dotnet add package Microsoft.EntityFrameworkCore.Design --version 8.0.x

Defensive patterns

Strategy: validation

Validate before calling

// Before scaffolding, confirm provider + design versions match
var designVer = typeof(DesignStrings).Assembly.GetName().Version;
var providerVer = providerAssembly.GetName().Version;
if (designVer.Major != providerVer.Major)
{
    throw new InvalidOperationException($"Provider {providerVer} mismatches EFCore.Design {designVer}");
}

Prevention

Keep EFCore.Design and every provider package on the same major+minor release.
Run scaffold against a known-good provider first to validate the pipeline.
Pin provider versions in Directory.Packages.props to avoid transitive drift.

When it happens

Trigger: Calling ScaffoldModel/Scaffold (or `dotnet ef dbcontext scaffold`) against a provider whose IScaffoldingModelFactory implementation returns null from Create(databaseModel, modelOptions). Reached once the database schema has been read successfully and the model-building step begins.

Common situations: A third-party or custom EF Core provider whose scaffolding adapter is incomplete or mismatched to the installed EFCore.Design version. Rarely, a provider version regression after upgrading EFCore.Design while the database provider package lags behind.

Related errors

AI-assisted analysis of dotnet/efcore@3a2006ef56 (2026-08-11). Data as JSON: /api/errors/ac701f7f849ab274. Report an issue: GitHub.

Appendix: source

Thrown at src/EFCore.Design/Scaffolding/Internal/ReverseEngineerScaffolder.cs:103

        }
        else if (!codeOptions.SuppressOnConfiguring)
        {
            _reporter.WriteWarning(DesignStrings.SensitiveInformationWarning);
        }

        codeOptions.ConnectionString ??= connectionString;

        var databaseModel = _databaseModelFactory.Create(resolvedConnectionString, databaseOptions);
        var modelConnectionString = (string?)databaseModel[ScaffoldingAnnotationNames.ConnectionString];
        if (!string.IsNullOrEmpty(modelConnectionString))
        {
            codeOptions.ConnectionString = modelConnectionString;
        }

        var model = _factory.Create(databaseModel, modelOptions);
        if (model == null)
        {
            throw new InvalidOperationException(
                DesignStrings.ProviderReturnedNullModel(
                    _factory.GetType().ShortDisplayName()));
        }

        if (string.IsNullOrEmpty(codeOptions.ContextName))
        {
            var annotatedName = model.GetDatabaseName();
            codeOptions.ContextName = !string.IsNullOrEmpty(annotatedName)
                ? _code.Identifier(annotatedName + DbContextSuffix)
                : DefaultDbContextName;
        }

        var codeGenerator = ModelCodeGeneratorSelector.Select(codeOptions);

        return codeGenerator.GenerateModel(model, codeOptions);
    }

    /// <summary>

View on GitHub (pinned to 3a2006ef56)