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.
System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.SqlServer.TransactSql, Version=18.104.22.168
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: