Asset Server fails to start (could not reattach to shared memory)

After a Windows Server 2012 reboot, the Unity Asset Server Control can't start the Unity server. It simply states "Could not start server".

I've tried:

• rebooting Windows again.

• Starting the Unity Asset Server service under Windows services.

• Changing the user of the Windows service to local system.

The following log is generated on the first attempt to start fron the Asset Server Control:

 LOG:  database system was interrupted; last known up at 2014-01-22 12:14:20 CET
 LOG:  database system was not properly shut down; automatic recovery in progress
 LOG:  record with zero length at 0/DF9B0DA0
 LOG:  redo is not required
 LOG:  database system is ready to accept connections
 FATAL:  could not reattach to shared memory (key=212, addr=01AC0000): 487
 LOG:  autovacuum launcher process (PID 3952) exited with exit code 1
 LOG:  terminating any other active server processes
 LOG:  all server processes terminated; reinitializing
 FATAL:  pre-existing shared memory block is still in use
 HINT:  Check if there are any old server processes still running, and terminate them.

Subsequent attempts at starting generates the following:

 FATAL:  could not reattach to shared memory (key=196, addr=01BC0000): 487
 LOG:  startup process (PID 4692) exited with exit code 1
 LOG:  aborting startup due to startup process failure

How do I solve this problem?