I now have 2 machines running Windows 10 on my domestic LAN, and I sign in to both using my Microsoft account. I usually work from one of them, and if I need to administer the other one, I log in to it using RDP. I decided to have different theme and console background & foreground colours, at least partly so I don't get confused about which machine I am operating! Imagine my puzzlement when the settings I had made on one machine mysteriously appeared on the other and vice versa. I had skipped Windows 8 and didn't realize that if you sign in using your Microsoft account, all your Windows 10 machines will have certain settings (things like your desktop theme, browser settings, and passwords) synchronized provided that SYNC is enabled on each machine. (It is enabled by default). I wonder if anyone else has been surprised by this?
My only SURPRISE was that the sync occurs across different versions. When I originally changed Windows 10 to re-add coloured title bars via a tweaked theme FILE, I returned to my Windows 8.1 system to find that it had synced the theme file and said theme file didn't work so well on Windows 8.1.Hello trout, now you are able to use different themes on your machines having sync settings enable. However windows 10 has an universal toggle for the Sync your settings but also provides additional option like "theme", "password", "language preferences" ease of ACCESS and other windows settings. So simply Turn on the universal setting and disable the theme synchronization. You can also take help from here:-


How to Customize Sync Settings on Windows 10