I am another one who - after creating a resource group - find that one of the NICs is "stuck" and won't delete. This resource group is "abruce-tc3-dnsserver" and the problem is: "Failed to delete subnet 'subnet'. Error: Subnet subnet is in use by abruce-tc3-dnsserver/providers/Microsoft.Network/networkInterfaces/nicr7d2sfmvxiag4/ipConfigurations/ipconfig1'>nicr7d2sfmvxiag4/ipconfig1 and cannot be deleted. In order to delete the subnet, delete all the resources within the subnet. See aka.ms/deletesubnet." Ah, but there are no resources in that subnet listed. I attempt to delete the NIC and the console says "Success!" ... but then a refresh on the console shows the same NIC still there. And - if I read another answer - M$ wants to charge for this error via a support plan? Is that a serious response? In the bad old days (circa 2000) AWS ran into this situation frequently - VMs wouldn't stop, wouldn't delete, same thing for the dependent resources. Never did I read that AWS would charge the user via a support plan to delete these erroneous resources.