I gave up on booting the VMs. I was able to access files in the non-encrypted VMDK via 7-Zip, so I'm just rebuilding from scratch. The encrypted VM was pretty generic for testing, so it can be rebuilt without too much problem.
In creating a VM on this new system, I did get a prompt that encryption is required. I must have chosen to encrypt everything and somehow not saved the key (or assumed I would remember it). This time I'm encrypting the minimal, so if something like this happens again, at least the VMDK should be accessible (via 7-zip).