login to any of the interactive machine(unt3int01-05), run the following commands

#localSetupATLAS  

or run

#source /cvmfs/atlas.cern.ch/repo/ATLASLocalRootBase/user/atlasLocalSetup.sh

List the available versions of root

#  showVersions root

Select one of the above listed versions,

#lsetup "root 6.14.04-x86_64-slc6-gcc62-opt"

-- WenjingWu - 21 May 2019