Hello,
the database is present. only one table (content_field_vmhost) in that database got deleted months ago.
I restarted in the past the vCenter Orchestrator Service 5.5.0 (Windows, build in with vCenter Server) a lots of time before I upgraded to 5.5.1. With Version 5.5.0 was no Problem after restarting, only after the upgrade to 5.5.1 i run into the error.
Sems to be that the database Content is somewhere (outdated) cached.