What happens?

This is a problem with Microsoft SQL Server. You may be unable to log into your SQL Server database.

When The SQL Server (SQLEXPRESS) service ... you shoud do following

The master database may have been corrupted. You may have to rebuild your master database, start SQL Server in single-user mode, and then restore the latest backup of the master database. In many cases, the incidence of this error code may be indicative of other problems; that is, there may be a deeper root cause to the problem that is not readily apparent. Find the root cause to determine what triggered the corruption to begin with.

After you have rebuilt your master database, update to the latest version or patch to make sure you are running the latest version of SQL Server.

TipFor more information, please see: How to fix Database error #3417