Database Project build fails Could not load file or assembly Microsoft.SqlServer.TransactSql, Version=12.0

This error can take place when Visual Studio 2013 is updated to Update 4 and extended Transact-SQL verification is enabled on the database project.

Error message:

System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.SqlServer.TransactSql, Version=12.0.0.0

To fix this issue, uncheck the Enable extended Transact-SQL verification option from the project properties.  If you wonder why this happened, the feature was deprecated and has been removed from the latest SQL Server tooling update which is what takes place when using VS2013 Update 4.

Database Project Properties

Microsoft Reference VS2013 Update 4:

 http://support.microsoft.com/kb/2994375