Depending on how you have your UI configured, Loop Tools will only become available if you are in the Edge sub-object selection of an editable polygon object, in the location indicated in the screen capture.  Can you guys take a screen capture of your ribbon at that location in edge sub-object mode?

I don't believe the ribbon structure changed in any version since 2011, but 2015 may have moved things around, not sure.  Still, it should be available if you map it to a hotkey.  I know it hasn't been removed from the software.

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