Despite restarting the computer, this app would not install, instead stating “Restart Required, a computer restart is required”

Slightly frustrating that the supplier of the software was not able to resolve the problem and it was left to me to try to figure it out for our customer.

The supplier / developer ought to know exactly what it is checking when it says Restart Required. I could see that their support team had checked the usual PendingFileRenameOperations stuff. I checked anything else I was aware of too such as Windows Update RebootRequired.

In the end I used process monitor to capture all registry access, filtered by the installer application. There were of course 10s – 100s of thousands of rows to sift through, but I filtered for ‘update’ or ‘restart’ etc. and found the part of the trace where it was doing these checks, and one by one looked at them in the registry.

In this instance it was HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\Services\Pending

I changed this to notPending, and lo-and-behold all good.