Error 1 Build failed due to validation errors in C:\projects\webapp1\Database.dbml. Open the file and resolve the issues in the Error List, then try rebuilding the project. C:\projects\webapp1\Database.dbml

The package Visual Studio use to build a LinqToSql database is marked to be skipped, so a quick reset of the “skip loading list” will resolve this issue.

1. Open a command prompt and navigate to : <visualstudiofolder>\Common7\IDE

2. Then execute : devenv.exe /resetskippkgs