Registry key / GPO to disable and block Windows 10 upgrade?
Solution 1:
According to this article you can add the following registry entry to disable Get Windows 10:
[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Gwx]
"DisableGwx"=dword:00000001
Try HLM\Software\WOW6432Node\RegisteredApplications\GWX and rename it.
Solution 2:
To properly disable the Windows 10 upgrade as recommended by microsoft I would advise reading the following article:
Ref: https://support.microsoft.com/en-us/kb/3080351
Computer Configuration
To block the upgrade by using Computer Configuration, follow these steps
Click Computer Configuration.
Click Policies.
Click Administrative Templates.
Click Windows Components.
Click Windows Update.
Double-click Turn off the upgrade to the latest version of Windows through Windows Update.
Click Enable.
Policy path
Computer Configuration / Administrative Templates / Windows Components / Windows Update Policy
Setting: Turn off the upgrade to the latest version of Windows through Windows Update
Windows registry
Important Follow the steps in this section carefully. Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
To suppress this offer through the registry, specify the following registry value:
Subkey: HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate DWORD value: DisableOSUpgrade = 1
Solution 3:
It's this guy: KB3035583. You may want to script a wusa.exe /uninstall for this one if it's already in the wild. This has been big news today, as Microsoft put this out last Patch Tuesday, and somehow forgot to mention the time-delay sales pitch set for June 1st.
Normally you would block this update in WSUS/SCCM. Of course, in this case you couldn't have known what to block. I certainly didn't get a notification from my MS team in my Advance Notice emails.
The folks over at SuperUser are ALL over this today as well:
https://superuser.com/questions/922068/how-to-disable-the-get-windows-10-icon-shown-in-the-notification-area-tray