Virtual Exchange server become unresponsive after Hyper-V integration services update

I've seen the three times now, and this issue effects both Exchange 2013 and Exchange 2016 installations.

The long and short is that if you have a Windows 2012 R2 virtual machine with either Exchange 2013/2016 installed and you upgrade the Hyper-V integration services the VM gets stuck on the next reboot. After about 30 minutes the login window appears but after trying to login the VM runs like a dog.

The fix is simple but painfully slow.

1. Shutdown the VM, you might have to reset it.
2. Attach a Windows 2012 R2 ISO to the VM
3. Start the VM and press a key to boot from the ISO
4. Select the Repair Windows option and get to the CMD prompt
5. Next alter the boot configuration so you have the option to boot into safe mode.
6. At the CMD prompt type:
   bcdedit /set {bootmgr} timeout 15
7. Reboot the VM and remove the ISO
8. You might find Windows wants to back out the failed updates from the previous boot.
9. At the Windows Boot manager select Safe Mode.
10. Once windows boots you will need to login and disable the Exchange services.
11. Open a PowerShell prompt and enter this command.
    get-service -Name MSE* | ?{$_.Starttype -eq "Automatic"} | Set-Service -StartupType Disabled
12. Now reboot the VM, you can ignore the Boot menu.
13. After Windows starts and you have logged in you can insert the Integration Services disk again and apply the update. Note you might find Windows plays up a bit as Exchange isn't working now.
14. Reboot the server, this time it shouldn't get stuck at "Getting Windows Ready"
15. After you have restarted and logged in you can enable the Exchange services once more by entering this command.
    get-service -Name MSE* | ?{$_.Starttype -eq "Disabled"} | Set-Service -StartupType Automatic
16. One last reboot and everything should be back to normal.

Microsoft has a lot to answer for here, the first time you see this it's really scary stuff.