I realize this is an older thread but I wanted to thank all of you who participated and updated with information to see it through. We're migrating company systems from another company we bought into our domain, they have SCCM and we have SCCM. Could not figure out why their systems would not populate Software Center after they were migrated. It looks like their SCCM server setting remained in place even after the CCMClean and a reboot. Thanks to the detailed information you guys provided I was able to find that and I wanted to thank you :)