Source: http://www.howtogeek.com/218856/how-do-you-disable-the-get-windows-10-icon-shown-in-the-notification-tray/ Date: September 2015
Microsoft is offering it as a free upgrade to most qualifying current Windows owners. They’re also pulling out the stops when it comes to making you, the average everyday Windows user, aware of its existence.
This includes adding a “Get Windows 10” icon and dialog to user’s system trays, which has alarmed quite a few people, who aren’t sure if it is some kind of trick or malware. Let us say with no uncertainty, it is not, but it is a little underhanded and annoying on Microsoft’s part.
This new icon and its resulting dialog are actually part of an application that appeared in late April 2015 as a recommended Windows update (KB3035583).
Open the Task Manager and navigate to “Task Scheduler Library” » Miscrosoft » Windows » Setup » gwx. Right-click on each item and disable. You may also want to remove the “GWXTriggers”. They may be locked you will have to remove the registry enties here:
ReBoot the computer.
To remove KB3035583, first open Windows Update and click “Installed Updates” in the bottom-left corner. To quickly find KB3035583, you can sort by name. Once you’ve located it, right-click and choose “Uninstall”. When you select to uninstall this update, you’ll be asked to confirm and then you will need to restart your computer. When you select to uninstall this update, you’ll be asked to confirm and then you will need to restart your computer.
KB3035583 will return if you don’t hide it from the update list. If you have Windows updates set to download and install automatically, this means that if you uninstall this update, it will be reinstalled automatically a few days later.
To hide the KB3035583 update and prevent it from being reinstalled, right-click on it in the Windows Update application and select “Hide update”.
After, the update’s selection box will be grayed out and cannot be checked. From hereon, the update will be hidden whenever you reopen Windows Update unless you decide to restore it.
There’s also a registry hack that you can use to prevent the icon from showing up.
You can open the the registry editor (regedit) and navigate to “HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Gwx” and set “DisableGwx” to “dword:00000001”
open notepad, create a new blank file, copy the text below to the file and save it as “StopWin10Prompt.reg”
NOTICE: That does NOT have the file extension .txt, it MUST be .reg.
Save that file to your Documents folder or the desktop, and then double click it. When you reboot the computer the Update Prompt should not come back. You can delete the .reg file.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Gwx] "DisableGwx"=dword:00000001