The model backing the 'ApplicationDbContext' context has changed since the database was created

Just in case anyone else stumbles upon this that was doing a database first implementation like me.

I made a change by extending the ApplicationUser class, adding a new field to the AspNetUsers table, and then had this error on startup.

I was able to resolve this by deleting the record created in the __MigrationHistory table (there was only one record there) I assume EF decided that I needed to update my database using the migration tool - but I had already done this manually myself.

This worked for me - no other changes required.

DELETE FROM [dbo].[__MigrationHistory]

This post fixed my issue. It's all about adding the following line in Application_Start() in Global.asax :

Database.SetInitializer<Models.YourDbContext>(null);

However it cause database recreation for every edit in your model and you may loose your data.