In vCenters, when I replaced the vmxnet3 network adapter on the VM with a vmxnet adapter and clicked OK, I encountered an issue. After attempting to switch back to the vmxnet3 adapter, the VM’s ‘edit settings’ Virtual Hardware tab was blank, regardless of whether the VM was powered on or off.
Solution: I logged into the ESXi host where the VM was located, opened the VM’s settings, and removed the vmxnet adapter. After removing it, the information reappeared under the Virtual Hardware tab, and I was immediately able to attach the correct vmxnet3 adapter.