If you’re trying to install or update packages via yum on a RedHat /CentOS server and you keep getting ‘Multilib’ errors along the lines of:
Protected multilib versions: openssl-1.0.1e-42.el6_7.4.x86_64 != openssl-1.0.1e-42.el6.i686
Then this means that you already have a 32bit version of a package and you’re trying to install a 64bit version (either by direct installation or as a dependency), or vice-versa. Generally these days you will be operating on a 64bit system so this issue can be very easily fixed by running the following
yum remove *.i386 *.i486 *.i586 *.i686
And then installing the 64 bit versions (these should be the defaults) of the offending packages.
I encountered this when trying to use a 64 bit CentOS image as an AWS server due to 32 bit packages being pre-installed. Good grief it took me a while to figure out!