A colleague pointed me to the inability 'to view / modify its Visual Studio TFS Work Items. Needless to say Windows does not extrapolated dall'eventviewer anything useful to the resolution of the problem, so 'I opened the TFS Project Portal and saw that the list of Work Items was visible correctly, but when you try to view the details of an item might be incurred in the error message "TF51300 Either is denied access to the database, or the item does not exist." .
After a quarter of an hour (unsuccessful) I thought I turned to Google to use the "old trick" of remove and replace:). In practice I have removed and then re-added the security group or user to Active Directory security by TFS / SPS and the problem 'disappeared.
