When trying to move a VM to another folder, I got this error:
The operation is not supported on the object
This is a bug. To fix this I converted the VM into a template (right click the VM, convert to template), then moved it to the folder I wanted and converted it back into a VM. To my knowledge, there are no prerequisites for moving a VMware VM to another folder. I tried doing it when the VM was powered off, still the only way to fix it was by converting it to the template then back again!