By: Chogan

Hi Nate,
Thanks for the comment/question. As you observed, any VM using a VMDK must be powered off before a VMDK can be grown (kb.vmware.com/kb/1007266)
This is the reason for the file lock, and specifically isn’t related to MSCS. I don’t believe there is any way around it (and clearing the lock while the cluster is still active isn’t recommended). Sorry.
Cormac