This article explains how to resolve the following error from migrating from PMX v5 to PMX v6.
ERROR: Command failed (255): 'su - pmx6 -c '/opt/pmx6/bin/pmx-env pmx-database stop'': Known to apply to the following Sophos product(s) and version(s)
The pmx-database program must only be run as the pmx user.
Migration script has terminated with error.
PureMessage for Unix 6.0
Linux & FreeBSD
What To Do
In the pmx 5 configuration directory edit the file pmx.conf and remove the line that references the following.
user = pmx
Save the file and return to the pmx6 user and re-run the pmx-v6-migrate script.