You may have noticed that some of your computer accounts are not showing “online” in the SBS Console. The purpose of this post is to shed some light on why you may see this and how this information is obtained by the server. Status information for your machines is displayed under the Network > Computers sub-tab in the SBS console. The console will only display status information for domain-joined computers from the following three OUs: OU=Domain Controllers,DC=Domain,DC=local; OU=SBSComputers,OU=Computers,OU=MyBusiness,DC=Domain,DC=local;
OU=SBSServers,OU=Computers,OU=MyBusiness,DC=Domain,DC=local

Full Article