Hi,
Workflows created by the users are stored not on the file system but in the database. You should try to restore them from there.
vRO 6 appliance comes pre-configured with an internal Postgres database so unless you changed the default configuration your workflows should be stored inside it. Here is another thread showing how to backup/restore the internal Postgres database - https://communities.vmware.com/thread/449663
The information in the thread above is for vCO 5.1 but it is also applicable for vRO 6; just the script to look at for DB name, DB user and DB password is at different location - instead of /opt/vmo/appliance/dbd/create_db.sql (vCO 5.1) it is now located at /usr/lib/vco/firstboot/dbd/create_db.sql