Howdy, I found out that there is new Red Hat branding in yum. 1. Get newest yum. 2. Move all repos to different location (probably enable=0 also would work - not tested), and disable any other repo (if there is repo enabled from another sources/plugin). 3. Try to update the system. One-liner: "sudo yum update yum -y && mkdir repos && sudo mv /etc/yum.repos.d/* repos/. && sudo yum update" yum update returns: """ There are no enabled repos. Run "yum repolist all" to see the repos you have. To enable Red Hat Subscription Management repositories: subscription-manager repos --enable <repo> To enable custom repositories: yum-config-manager --enable <repo> """ Patch responsible for change: BZ-1175309-enable-repos-instruction.patch This patch has number 230 in spec file. Bests, Alex PS. http://ftp.scientificlinux.org/linux/scientific/7.4/SRPMS/SL/ doesn't contain current yum version. yum.ini from http://ftp.scientificlinux.org/linux/scientific/7.4/SRPMS/vendor/yum-3.4.3-154.el7.src.rpm states that yum should be sl7, but yum from http://ftp.scientificlinux.org/linux/scientific/7.4/x86_64/os/Packages/ is el7.