WSUS database by default tend to be on the C drive, which is all good until you start to run out of space.

The problem then comes in moving the database from C: to often your data drive in my example D:

The biggest problem people have in doing this is actually connecting to the database.

Most people like point and click tools like SQL Server Management Studio or Express edition
http://www.microsoft.com/downloads/details.aspx?FamilyId=C243A5AE-4BD1-4E3D-94B8-5A0F62BF7796&displaylang=en

MAKE SURE YOU HAVE A BACKUP BEFORE YOU START THIS.

To connect to the database you need to use the following address as the Server Name:

file://pipe/mssql$microsoft##ssee/sql/query

I connected through using this address as Administrator which seem to work ;-) Once you have a connection in the database.

The rest becomes alot simplier in terms of moving the SUSDB . Expand the database list and you should see SUSDB .

Before you do this though make a note of were the files are !! ldf and the mdf ;-)

Right click on the database

Task -> Detach

you will need to select the option "Drop Connections" otherwise it will normally fail to detach.

Once you have detached the database. *COPY* ldf and mdf file to your new location.

Once copied you simple need to Attach the database back in again. Right click on Database -> Attach

Locate the mdf file in the new location and attach the database back.
Once you are happy that database is re-attached correctly and you have checked the system is working, you can delete you old mdf and ldf file. Personally I just copied them off onto a USB drive just in case. You should then have some space back on your C drive.

[UPDATE]
Make sure you check the permissions on the database before you start this procedure just in case.