I was deploying a build on a cloud test machine with its own SQL Server and data. I was testing a sync function (a mobile handheld grabbing information from a server) and got the following error.
Unable to update the EntitySet ” because it has a DefiningQuery and no element exists in the element to support the current operation.
What it ended up being for me was for some reason, my primary key was not set on the table that threw this error. Beats me how it happened since it was taken from a backup of my dev PC’s database, but after I added a primary key to the table and updated my EDMX, all was well. Hope this helps!