Fix : Error : Error 15401: Windows NT user or group ‘username’ not found. Check the name again.
This is quite a famous error and I was asked to write about it by couple of readers. The reason I was not writing about this as the solution of this error is very well explained in Book On Line. All the potential causes and their solutions are explained well here. This post/article should be considered as book mark to solution.
Refere Microsoft Help and Support : How to troubleshoot error 15401
Reference : Pinal Dave (http://blog.SQLAuthority.com)