For various reasons which seemingly fail the necessary/sufficient tests with the benefit of hindsight, I attempted to migrate a shell machine which is the beach front from which I work (not a production server) from CentOS 5.5 to Scientific Linux 5.5 yesterday. Karanbir is quoted on this list as having said something like: "All that you should need to do is install centos-release, remove redhat-release rpms and just yum update the machine, which should bring in all packages changed by CentOS ( since they will have a slightly higher E-V-R )." In other words, is there a get out of jail card based on Karanbir's stanza which will return the machine to a consistent state without a fresh install? The results from the bad migration are below the sig. The stanza used was from the SL mailing list, namely: "To be REALLY sure of a full conversion one might try: yum reinstall $(rpm -qa --qf "%{name}.%{arch} %{vendor} \n" | \ grep -i centos | cut -d ' ' -f 1 | sort | uniq | grep -v kernel) Need special handling for kernel and kernel-devel as you will get messages about multiple versions being allowed, and cutting off the limb on which you are standing is not recommended." In short, I pray for the community's thoughts about how to proceed with either going forward, reverting back to Centos 5.5 or even RHEL 5.5 without having to do a fresh install. THANKS for your help. kind regards/ldv === [root at shell work-2011-01-25-migrate-centos55-to-scientific-linux55]# yum list installed | grep -i centos geronimo-specs.i386 1.0-0.M2.2jpp.12.el5.centos installed geronimo-specs-compat.i386 1.0-0.M2.2jpp.12.el5.centos installed nss.i386 3.12.8-1.el5.centos installed nss-devel.i386 3.12.8-1.el5.centos installed nss-tools.i386 3.12.8-1.el5.centos installed [root at shell work-2011-01-25-migrate-centos55-to-scientific-linux55]# BUT, more devils in the details are: [root at shell SL-rpms]# rpm -ivh kernel* warning: kernel-2.6.18-194.32.1.el5.i686.rpm: Header V3 DSA signature: NOKEY, key ID 192a7d7d Preparing... ########################################### [100%] package kernel-headers-2.6.18-194.32.1.el5.i386 is already installed package kernel-2.6.18-194.32.1.el5.i686 is already installed package kernel-devel-2.6.18-194.32.1.el5.i686 is already installed file /boot/.vmlinuz-2.6.18-194.32.1.el5.hmac from install of kernel-2.6.18-194.32.1.el5.i686 conflicts with file from package kernel-2.6.18-194.32.1.el5.i686 file /boot/System.map-2.6.18-194.32.1.el5 from install of kernel-2.6.18-194.32.1.el5.i686 conflicts with file from package kernel-2.6.18-194.32.1.el5.i686 file /boot/config-2.6.18-194.32.1.el5 from install of kernel-2.6.18-194.32.1.el5.i686 conflicts with file from package kernel-2.6.18-194.32.1.el5.i686 file /boot/symvers-2.6.18-194.32.1.el5.gz from install of kernel-2.6.18-194.32.1.el5.i686 conflicts with file from package kernel-2.6.18-194.32.1.el5.i686 file /boot/vmlinuz-2.6.18-194.32.1.el5 from install of kernel-2.6.18-194.32.1.el5.i686 conflicts with file from package kernel-2.6.18-194.32.1.el5.i686 file /lib/modules/2.6.18-194.32.1.el5/kernel/arch/i386/crypto/aes-i586.ko from install of kernel-2.6.18-194.32.1.el5.i686 conflicts with file from package kernel-2.6.18-194.32.1.el5.i686