I have seen this error at one of my customers sites, the main problem we had is to get to the the source of this error.
So what were the symptoms?
The SQL Server was installed to serve the TFS 2010, in the installation we saw no problem at all and the server worked well.
The first time we noticed that we have a problem was when we tried to backup the databases using the SQL Server Maintenance Plan, we have received an error from the plan’s job.
when trying to understand what the problem is we saw no errors at the “Windows Event Viewer” , in the logs we saw that the “Could not obtain information about windows NT…”
After a lot of research and many Google links that gave us nothing we found the real problem:
So what do you need to do next?
First of all you need to check that the user that runs SQL Server Services has sufficient privilege in the domain, in most cases it will be sufficient to have the basic user domain privilege to fix this problem.
What append in our case is that the user that runs the SQL Server Services had two groups, the basic User Privilege and another group that some of its security settings Denied the required privilege.
What we did is just removed this group and all worked well.