Hello Christoph, it looks like you've hit on a bug in the upgrade script which manipulates the repos. It should have removed "samba-*" from the "exclude" line but did not. The script fails as the string to remove is the last one in the exclude line. You can remove manually all three occurrences of "samba-*" from /etc/yum.repos.d/clearos-centos.repo or wait for us to push an update.

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You can remove the .rpmnew and .old files from here if you want.
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