After a recent Owncloud 8.o.x update I started getting this error being logged whenever the owncloud cron job run. To resolve the issue I had to change the cron job to be run as the user apache.
su -s /bin/sh apache -c "php -f /path/to/owncloud/cron.php"
The webserver on CentOS is run under the user apache, on other linux flavous it’s www-data to find out what it is on your system just check the error being logged it will log the user running the webserver.
Console has to be executed with the same user as the web server is operated
Current user: someuser
Web server user: apache <- This is the user you want.
Unexpected error!