I use Visual Studio 2013 Professional Update 4 in combination with multiple SQL Server 2012 Enterprise servers/instances. The Idea was to create a Version controlled deployment using a Visual Studio Solution with SQL Server Projects.
However for some reason the "Update Target" and "Generate Script" button is disabled.
I can update the local database project from the sql server database but the other way around is not working. (see screenshot)
Google is not helpful at all although I found a few people with a similar problem.
Update target button is disabled after schema comparison
VS2012: Schema compare, update button disabled
VS2012 Schema compare buttons disabled
But none of this questions/blogposts is about Visual Studio 2013 and in addition none of the proposed solutions is working for me.
Question: Why is the Update Target button disabled and what do I have to change to fix this?
Note: Of course, I'm using the latest version of SQL Server Data Tools(12.0.50318.0)
This was driving me nuts, as well. I finally noticed a "warning" message stating "Cannot generate deployment plan due to an internal error". Because of this, the Update and Generate Script buttons were both disabled.
I resolved this by closing Visual Studio, navigating to the folder containing the Database project and removing all (*.dbmdl) files. I then restarted Visual Studio, re-ran the compare schema and the Update button was enabled.
The tip that helped me was to look at the error list. (View Menu, Error List). Once I cleared the errors (just the errors, the ones with the red X) I was able to compare the schema again and the Update and Generate Scripts buttons were both enabled.
来源：https://stackoverflow.com/questions/29277339/update-target-button-is-disabled-in-sql-server-database-schema-comparison