I struggled to go from OMV 2 to 3 but finally got it working. Then I installed duplicati. Rebooted. Got this message in the GUI which renders using the GUI impossible because the error will not go away (just keeps popping up forever). I researched on this forum and others and I am clueless:
OMV\ExecException: Failed to execute command 'export PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin; export LANG=C; free -b -t -w 2>&1' with exit code '1': free: invalid option -- 'w'
Thanks for the help.