Error Processing Tabular – Method Not Found

Very quick blog post today. While setting-up a development server at a client who is still using SQL Server 2012, I was greeted with the following error while processing a Tabular model:

Errors in the high-level relational engine. The following exception occurred while an operation was being performed on a data source view: Method not found: ‘System.Threading.Tasks.Task`

A quick search indicated other people have struggled with this issue, but no solution were provided in the forums. After digging a bit more, I found related issues but rather for .NET developers, so it’s not for Tabular only. The solution was actually quite easy: upgrade the server to the latest .NET environment. After rebooting the server, I could finally process my Tabular model.