After trying to export a VM and cancelling the export it could happen that the VM is nolonger responsive (no start, unregister, delete, … possible)
The hostd.log (in the /var/log directory on the ESXi) will show an error similar to:
2021-09-07T10:55:19.583Z error hostd[2099544] [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/XXXXXXXX-05c01598-574e-88d7f6d5ef52/myvm/myvm.vmx opID=esxui-6c72-aafe user=root] Invalid transition requested (VM_STATE_EXPORTING -> VM_STATE_DELETING): Invalid state
2021-09-07T10:55:19.583Z warning hostd[2099544] [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/XXXXXXXX-05c01598-574e-88d7f6d5ef52/myvm/myvm.vmx opID=esxui-6c72-aafe user=root] Method fault exception during VM destroy: Fault cause: vim.fault.InvalidPowerState
It seems the VM is somehow stuck in the Exporting-state and therefore no other operation is possible on the VM .
As a workaround log in to the ESXi Host and restart the Management Agents (https://kb.vmware.com/s/article/1003490)