dotnet/efcore · warning · OperationException

Changes have been made to the model since the last…

Error message

Changes have been made to the model since the last migration. Add a new migration.

What it means

HasPendingModelChanges instantiates the context and asks the database provider whether the current model differs from the last migration's target model. If the snapshot-based diff reports pending changes, EF throws to signal that 'dotnet ef migrations add' must be run before further migrations work. This is the command backing the 'has-pending-model-changes' diagnostic, not an automatic gate inside AddMigration.

Solutions

Add a new migration: 'dotnet ef migrations add <Name>' so the model snapshot and the latest migration target model agree.
If the diff is spurious (provider/resolver differences across environments), regenerate the model snapshot by adding then removing an empty migration.
Ensure the context configuration at design time matches runtime (same provider, same OnModelCreating).

Example fix

// before: model edited, no new migration
dotnet ef database has-pending-model-changes
// Throws
// after
dotnet ef migrations add AddProductRating

Defensive patterns

Strategy: validation

Validate before calling

// Before checking, you can pre-flight the diff yourself
if (context.Database.HasPendingModelChanges())
{
    Console.Error.WriteLine("Model has pending changes; run 'dotnet ef migrations add'.");
    // exit non-zero instead of letting the command throw
}

Try / catch

try { ops.HasPendingModelChanges(contextType); }
catch (OperationException ex) when (ex.Message.Contains("Changes have been made to the model"))
{ /* scaffold a new migration */ }

Prevention

Run 'migrations add' immediately after model edits.
Gate CI on a clean model snapshot.
Keep design-time and runtime provider/config in sync.

When it happens

Trigger: Invoking MigrationsOperations.HasPendingModelChanges(contextType) (the EF tool 'database has-pending-model-changes' / equivalent) after the model has been edited (entity added/removed, property changed, etc.) without a corresponding new migration. context.Database.HasPendingModelChanges() returns true.

Common situations: Editing an entity or DbContext configuration then running the pending-changes check in CI or a pre-commit hook before scaffolding a migration; switching provider or adding an index/column; reverting a migration's model changes but not its files.

Related errors

AI-assisted analysis of dotnet/efcore@3a2006ef56 (2026-08-11). Data as JSON: /api/errors/7f44a87af7fa3189. Report an issue: GitHub.

Appendix: source

Thrown at src/EFCore.Design/Design/Internal/MigrationsOperations.cs:375

        return files;
    }

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    public virtual void HasPendingModelChanges(string? contextType)
    {
        using var context = _contextOperations.CreateContext(contextType);

        var hasPendingModelChanges = context.Database.HasPendingModelChanges();

        if (hasPendingModelChanges)
        {
            throw new OperationException(DesignStrings.PendingModelChanges);
        }

        _reporter.WriteInformation(DesignStrings.NoPendingModelChanges);
    }

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    [RequiresDynamicCode("Runtime migration compilation requires dynamic code generation.")]
    public virtual MigrationFiles AddAndApplyMigration(
        string name,
        string? outputDir,
        string? contextType,
        string? @namespace,
        string? connectionString)

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