Event details
Back in August I asked about the possibility of performing an in-place reinstall of Windows without having to remove the device from Intune update management and have someone manually press the "Reinstall now" button in the Settings app under "System > Recovery". At that time I was told it was not possible.
I have since learned from this blog post that there is in fact a way to do this. Apparently Microsoft Support is telling customers that they can simply create the following registry value to initiate the in-place reinstall:
Key: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion
Value name: AllowInplaceUpgrade
Value data: 4
Value type: REG_DWORD
I can confirm that on a machine where the in-place reinstall has been manually initiated, the value is present, except the value data is 1 instead of 4.
Unfortunately, there doesn't appear to be any official documentation about this function, aside from an off-hand reference to the value name on this support page: Windows Update Troubleshooter for devices experiencing recurring issues installing monthly security updates - Microsoft Support
Can someone please provide the technical details? What is the significance of the value data? Does it change the behavior in some way? And why isn't this documented anywhere?
MicrosoftRyanSteele-CoV Thanks for the question. This is not a key/value that we publicly document, so we don't have anything to share here. I can tell you, though, that this reg key is used by some Windows Update components as a flag to direct the client to offer or perform an in‑place upgrade (IPU) under certain remediation or admin‑initiated scenarios. Sorry we can't get deeper into the nitty gritty here.
Thanks for responding. If you are able to share feedback with whoever is responsible for this: as long as Windows is prone to getting into a state where updates can no longer be installed, administrators need a way to remotely initiate an in-place reinstall. This is a security issue.