How to refresh AD security group on Sql Server permissions I am using Sql Server 2008 on Small Business Server 2003; client is using WinXP. 

I added a user to my Active Directory Security Group; Why can't this user immediately access the database? It seems there is a delay before the user is recognized in Sql Server. 

I am using AD Security Groups for permissions expressly so that I don't need to add individual users in Sql Server. So effectively I don't need to do anything but add the user to the AD Security Group in order to grant access.

But for some reason Sql Server doesn't immediately recognize the addition. I've seen this a number of times. I add the user to the group but that user can't access data until the next day. It seems that it doesn't query the Active Directory in real time. Can you confirm that is so?

What do I need to do so that Sql Server "refreshes" the list of users from Active Directory?
The user need to log off of their workstation and log back on.  That's why the changes appear to take effect the next day.  The reason for this is that when the user logs on the next day they get a new token from the domain controller and this token contains the list of domain groups that they are a member of.  This token with the list of domain groups is only updated when the user logs in to their computer, so if the user never logs out the token isn't ever updated.

There's also multi-site domain replication delays which need to be taken into account if your domain controllers are in different physical locations.