Thanks for the pointer. I had a slightly different problem, but your post pointed me in the right direction for a solution.
My VM took a good two or three hours to shut down (famously stuck at 95% for hours). When I tried to restart it, it said it couldn't lock the VMK file. Looked everywhere and couldn't figure out what had the file locked. Turned out two external ISCSI drives had gone off-line, and even though the error seemed to indicate that drive 0 couldn't be started due to file locked. It was failing to lock the 4th and 5th drives. I removed those failed hard drives from the VM's configuration, and restarted it perfectly fine. Thanks for the pointer!