We've got audit-certified machines at work that can't simply be upgraded so I had to research this a bit last week. The following is mostly for techies, but I'll see what I can do to make it more accessible later, when I get the chance. My apologies for not being able to do so right now, but I wanted to get the info out there.
Steps to block the upgrade:
Open the Registry Editor (search for regedit in the Start Menu and run it).
Set DisableOSUpgrade to 1 in HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
Set ReservationsAllowed to 0 in HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\OSUpgrade
(from
https://support.microsoft.com/en-us/kb/3080351 )
You'll need someone to use a Windows built-in utility called RedEdit to make the changes. I'm on a Linux box right now, next time I'm on a windows box I'll see if I can make a proper .REG file you can download and find somewhere to post it (unless someone beats me to it, please feel free to do so). It's something you'd download to your desktop, right click and select "merge". That's it.
Also to those who are more tech savy, the following updates will install a group policy that will block the upgrade (pretty much the same as making the Reg edits plus extra sauce)
https://support.microsoft.com/en-us/kb/3065987https://support.microsoft.com/en-us/kb/3065988
20 Feb 2016, 11:17 pm
