I have had several users saying Windows 10 Upgraded it’s self. In order to stop this we can create a registry key to stop this from happening.
HKEY_LOCAL_MACHINESOFTWAREPolicies
MicrosoftWindowsWindowsUpdate
You will need to create the “Windows Update” Key in HKEY_LOCAL_MACHINESOFTWAREPoliciesMicrosoftWindows and then create a 32 Bit DWORD named “DisbaleOSUpgrade” and set the value to Decimal of 1.