This can be due multiple cause, such as :Registering a virtual machine in the vCenter Server datastore browser may fail when the .vmx file name contains non-Basic Latin characters, for example, westあ表薔薇/west-ja.vmx or datastore path violates the expected format. Also, If a datastore corresponding to the given datastore path is not found. And,
If the file corresponding to the path does not exist on the filesystem. Even,
When a media store and its NFS datastore have the same NFS path root. To resolve this issue, please follow the KB 2013832.
Sincerely,
Rahul Parmar
VMware Support Moderator