We started noticing an inconsistency between Active Directory computer numbers and System Center item counts. After some forum searching I discovered the issue.
In SCCM go to Administration > Site Configuration > Sites > Click your site > then in the upper ribbon bar select Site Maintenance. (You can right click your site also). Here there are 2 settings we need to adjust.
- Delete Aged Discovery Data – Use this task to delete aged discovery data from the database. This data can include records that result from heartbeat discovery, network discovery, and Active Directory Domain Services discovery methods (System, User, and Group). This task will also remove aged devices marked as decommissioned. When this task runs at a site, data associated with that site is deleted, and those changes replicate to other sites.
- Delete Inactive Client Discovery Data – Use this task to delete discovery data for inactive clients from the database. Clients are marked as inactive when the client is flagged as obsolete and by configurations that are made for client status. This task operates only on resources that are Configuration Manager clients. It’s different than the Delete Aged Discovery Data task, which deletes any aged discovery data record. When this task runs at a site, it removes the data from the database at all sites in a hierarchy.
We’ve changed these to 365 days due to being K12 and there will be months (especially summer) some of these machines will not be used.