Upgrade from Plesk 11.5 to Plesk 12 failed with error:
ERROR while trying to add supplementary group 'lock-manager' for user 'psaadm'
Check the error reason(see log file: /var/log/plesk/install/plesk_12.0.18_installation.log), fix and try again
tac: write error: Broken pipe
The issue was caused since '
psaadm ' was not assigned to group '
psaadmmanually to group
# usermod -a -G lock-manager psaadm
# grep lock-manager /etc/group
# /usr/local/psa/bootstrapper/pp12.0.18-bootstrapper/bootstrapper.sh repair