I also encountered a similar problem. "yum clean all" did not resolve it, but *not* installing the CR prior to the update repo did. I think the problem is that my update script was still installing centos-release-cr-5.6 (the URL was hardwired, as I couldn't think of a simple way to get the correct one). The script also installs the CR repo prior to the update and uninstalls it afterwards, since I wasn't sure if the CR repo would continue to exist when 5.7 was released (the CR wiki page [1] says "The repository will go-away once the packages are released via the regular process"). However, it seems that the CR repo is still there, and a centos-release-5.7 upgrade is available through it. Is it safe/advisable to leave the CR repo installed in-perpetuity? Or do I need to remove it after using it, if I want to prevent potential yum-upgrade errors if it does go away? N 1. http://wiki.centos.org/AdditionalResources/Repositories/CR