You probably know the error message: operation impossible since file is locked.
If a VMDK is locked you can not start it inside a VM and you can not copy it.
The knowledgebase basically tells you to stop all processes that access the file and reboot.
This is supposed to fix the problem.
This documentation is not good enough.
In VMFS 6 following this advice may not be enough to release the lock.
This means that you basically lost the file as you can not read it anymore.
Trying to access it via Linux is also impossible at the moment.
Recent recovery third party tools like UFSexplorer also failed to read the vmdks in such a case.
Here is a recent case for your reference ....
Problem with locked virtual machine after esxi host crash
I have seen a couple of this cases recently so I started to investigate the issue,
Now I may have found a way to recover a VMDK that would other wise be a case for Ontrack or VMware Support.
My procedure requires a direct hexedit of the VMFS heartbeat- section so please do not ask for details at the moment.
I will post details once I know this approach is dafe.
Anyway I believe this is a bug in the way ESXi 6.5 handles the heartbeat section of a VMFS-volume.
This issue should never affect single host environements.
Feel free to contact me via skype if you run into this yourself.
Good to know whom to contact in such a case!