Question : SCCM 2007 collection by OU not showing all pc's

I have created a collection in SCCM 2007 and created a query based on "system resource - system OU name" and although there are around 100 pc's in the OU when updating collection membership its only returning about 10.

Any ideas?

Answer : SCCM 2007 collection by OU not showing all pc's

How is your AD System Group Discovery setup?

If neither the AD System or System Group Discoveries LDAP strings envelop the OU or parent OU, I believe you will have a problem.

system OU name is directly discovered by AD System Group Discovery if I'm not mistaken.

I would check the adsysdis.log and adsysgrp.log on the site system supporting the clients.  Run a search for the name of the OU where the clients should reside.  If that OU is missing, this reinforces that the OU is not being discovered.