Code first Database Migration

I added a new column to my object, and I issue add-migration command in Nugget manager console, The add-migration was successful however, when I issue the command to EF to update-database. it gave me this error "multiple identity columms specified for table 'Movies' only one identity column per table is allowed". I open the Movie object and check and ammend the ID column as well as the table in the server explorer matching the object but the error still persist, what will I do next, Anybody to help?