Remove-Unattached-NICs

Remove-UnattachedNIC.ps1

$deleteUnattachedNICs = $false

# List all unattached NICs
$unattachedNICs = Get-AzNetworkInterface | `
	Where-Object { $_.VirtualMachine -eq $null -and ($_.PrivateEndpointText -eq $null -or $_.PrivateEndpointText -eq 'null') }

# Iterate over the unattached NICs
foreach ($nic in $unattachedNICs) {
	# Find a lock for the NIC (or resource group/subscription/...)
	$lock = Get-AzResourceLock -ResourceName $nic.Name -ResourceGroupName $nic.ResourceGroupName -ResourceType 'Microsoft.Network/networkInterfaces'

	# If there is no lock
	if (! $lock) {
		# If this is a test run only
		if (! $deleteUnattachedNICs) {
			Write-Host "Would delete $($nic.Name)"
		}
		else {
			Write-Host "Deleting $($nic.Name)"

			try {
				# Delete the NIC
				Remove-AzNetworkInterface -Name $nic.Name -ResourceGroupName $nic.ResourceGroupName -Force
			}
			catch {
				Write-Host "Failed to remove $($nic.Name): $_" -ForegroundColor Red
			}
		}
	}
	else {
		Write-Host "Cannot delete $($nic.Name) due to resource lock"
	}
}