Upgrades should not rely on a specific username/group.
When upgrading Artifactory via yum/debian/rpm/deb, the upgrade script will ALWAYS try to create the artifactory group and user. This is the case even when the user/group running Artifactory has been set to a different username/group.
1. Perform a YUM installation of an older version of Artifactory (say 4.12.2)
2. Create a new user and group with a different name (say 'paco')
3. Change the ownership of all the relevant folders to the new user/group and set the new user in the default file
4. Start Artifactory and confirm the new user is being used
5. Delete user and group artifactory
6. Perform an upgrade (yum upgrade artifactory)
7. Observe the error