Date 1/1/2010 5:54:32 AM
Log SQL Server (Current - 1/1/2010 8:40:00 PM)
Source Logon
Message
Error: 18456, Severity: 14, State: 16.
Followed by something like this:
Date 1/1/2010 5:54:32 AM
Log SQL Server (Current - 1/1/2010 8:40:00 PM)
Source Logon
Message
Login failed for user 'DOMAIN\userid'. [CLIENT: 192.168.1.1]
You might just find you have this issue:
FIX: Error message when you try to use a SQL Server authenticated login to log on to an instance of SQL Server 2005: "Logon error: 18456"
http://support.microsoft.com/kb/925744
