Hidden Network Adapters in Azure VM and unable to access network resources

I have some Azure VM’s that I regulary Stop (deallocate) and Start using Azure Automation. The idea is to cut costs while at night or weekends, as these VM’s are not used then anyway. I recently had a problem with one of these Virtual Machines, I was unable to browse or connect to network resources, could not connect to the domain to get Group Policy updates and more. When looking into it, I found out that I had a lot of hidden Network Adapters in Device Manager. The cause of this is that every time a VM is shut down and deallocated, on next start it will provision a new network adapter. The old network adapter is kept hidden. The result of this over time as I automate shut down and start every day, is that I get a lot of these, as shown below: I found in some forums that the cause of the network browse problem I had with the server could be related to this for Azure VM’s. I don’t know the actual limit, or if it’s a fixed value, but the solution would be to uninstall these hidden network adapters. Although it is easy to right click and uninstall each network adapter, I wanted to create a PowerShell Script to be more efficient. There are no native PowerShell cmdlets or Commands that could help me with this, so after some research I ended with a combination of these two solutions:

• Device Management PowerShell from Technet Gallery: http://blogs.technet.com/b/wincat/archive/2012/09/06/device-management-powershell-cmdlets-sample-an-introduction.aspx
• Windows Device Console (DevCon.exe) http://msdn.microsoft.com/en-us/library/windows/hardware/ff544707(v=vs.85).aspx

I then ended up with the following PowerShell script. The script first get all hidden devices of type Microsoft Hyper-V Network Adapter and their InstanceId. Then for each device uninstall/remove with DevCon.exe. The Script:

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Set-Location C:\_Source\DeviceManagement

Import-Module .\Release\DeviceManagement.psd1 -Verbose

# List Hidden Devices

Get-Device -ControlOptions DIGCF_ALLCLASSES | Sort-Object -Property Name | Where-Object {($_.IsPresent -eq $false) -and ($_.Name -like "Microsoft Hyper-V Network Adapter\*") } | ft Name, DriverVersion, DriverProvider, IsPresent, HasProblem, InstanceId -AutoSize

# Get Hidden Hyper-V Net Devices

$hiddenHypVNics = Get-Device -ControlOptions DIGCF_ALLCLASSES | Sort-Object -Property Name | Where-Object {($_.IsPresent -eq $false) -and ($_.Name -like "Microsoft Hyper-V Network Adapter\*") }

# Loop and remove with DevCon.exe

ForEach ($hiddenNic In $hiddenHypVNics) {

1

$deviceid = "@" + $hiddenNic.InstanceId

.\devcon.exe -r remove $deviceid

}

And after a while all hidden network adapter devices was uninstalled: In the end I booted the VM and after that everything was working on the network again!