SSAS Tabular Error “The object reference not set to an instance of an object”
This just goes under the blog tag "Useless Error Messages". My instance of this error happened when I added a new calculated column. Finally I realized I had named the new column the same as another column in a different table. Changed one of the names and no error. Lesson learned: SSAS Tabular is picky about not having two columns named the same. So boys and girls, only you can prevent stupid coding mistakes...