Microsoft have already withdrawn it Windows 10 October 2018 Update (version 1809), but errors continue to appear. For example, there have just been reports of the operating system being turned off.
Yes, after installing Windows 10 October 2018 Update (version 1809) on computers where the operating system was already activated, the Windows watermark appeared on surface work. The watermark only appears on non-activated Windows. 
Of course the event brings too many problems for users of the operating system that no longer have the product key for their system. Another problem is that they can't find their key with some third-party app because their system isn't activated.
The only solution is to go back to the previous version of Windows 10, using the "roll-back" function and then find the product key to reinstall the Windows 10 October 2018 Update.
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- Windows 10 Note Disk Cleanup also deletes the downloads
- Windows Server 2019 ISO before the announcement
- Windows 10 S Mode at the touch of a button in Settings
