On a clean installation of Windows Server 2008 or 2008 R2, Virtuozzo Management Service (vzsrv) starts within 1 minute after the server reboot.
After the installation of all available Windows updates, it takes about 10-15 minutes for this service to start.
Until the service starts, it's impossible to connect to the hardware node via RDP.
Such behavior is recognized as a product bug PCWIN-18433.
Virtuozzo Management Service parses the list of updates and their content on each startup, and this procedure is very cumbersome.
The fix is included in VZU460066 update for Parallels Virtuozzo Containers 4.6 (release notes).