When running WSUS on a Small Business Server, the default location is the C: drive, when that drive gets full you need to move the content and the SQL database. Below are the steps to move the SQL database to another location.
1. Open command prompt and type: net stop “update services”
2. Next, at the command promt type: net stop w3svc (if it is SBS 2008 it will also stop the Terminal Services Gateway, remember to restart)
3. Open Microsoft SQL Express Management Studio (if you don’t have this, go to http://tinyurl.com/ynl9tv to download) and connect to the MICROSOFT##SSEE database, which is the WSUS database and the SharePoint databases in SBS 2008. You can’t just connect to the database normally, you need to type this in server name area: \.pipeMSSQL$MICROSOFT##SSEEsqlquery
4. Detach the SUSDB database, move the SUSDB folder to the new location and attach the database again with Management Studio
5. Restart the services: “update services”, “w3svc”, and “Terminal Services Gateway”