Software⏱️ 2 min read📅 2026-05-31

How to Fix: ASP.NET MVC - Attaching an entity of type 'MODELNAME' failed because another entity of the same type already has the same primary key value

Learn how to fix: ASP.NET MVC - Attaching an entity of type 'MODELNAME' failed because another entity of the same type already has the same primary key value.

Quick Answer: Try checking your system settings or restarting.

The issue you're experiencing occurs when trying to attach an entity of type 'AViewModel' to the context, but another entity of the same type already has the same primary key value. This is a common problem in Entity Framework (EF) 6.

🛠️ Step-by-Step Verified Fixes

Method 1: Using the Include Method with a Load Option of Include

  1. Step 1: In your controller, use the include method to load the related entities when attaching the AViewModel entity.

Method 2: Using a Separate Load Operation

  1. Step 1: Create a separate load operation for the AViewModel entity before attaching it to the context.

💡 Conclusion

By using either of these methods, you should be able to resolve the error and successfully attach the AViewModel entity to the context without any issues.

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