The quorum log checkpoint could not be restored to the cluster database. There may be open handles to the cluster database that prevent this operation from succeeding.
This error occurs when you try either to have a server join a cluster or to bring an application online. When a server joins an existing cluster, it downloads the entire cluster database from the node already in the cluster. Failure of the operation means another application has the HKEY_LOCAL_MACHINE\Cluster key open. An attempt to bring an individual application online can fail for the same reason: Another application has a handle open to the registry key that the application you're bringing online needs to update.
Close all other applications, and try the operation again (whether joining the cluster or bringing the application online).