I just came across very simple error and the solution was even simpler. While concatenating NEWID to another varchar string, I had to CONVERT/CAST it to VARCHAR and I accidentally put length of VARCHAR to 10 instead of 36. It displayed following error.
Msg 8170, Level 16, State 2, Line 1
Insufficient result space to convert uniqueidentifier value to char.
The code which I had ran earlier was as following.
SELECT 'GeneratedID:'+CAST(NEWID() AS VARCHAR(10)) AS NEW_ID
The solution of above error is extremely simple. I just increased the length from VARCHAR(10) to VARCHAR(36) and it worked fine.
SELECT 'GeneratedID:'+CAST(NEWID() AS VARCHAR(36)) AS NEW_ID
Reference: Pinal Dave (http://blog.sqlauthority.com)