This has me utterly mystified! My laptop is running Win 8.1 x64. On the same home network my PC (Win 7 Pro) is running a new Win 8 x86 install in a VM (VMware Player). Both were set up using the same Microsoft account rather than local accounts. What is sending me apoplectic is that if I change my desktop background on either system it causes the other to change too. If both systems have the same themes available then both will display the same theme. If not then the second system will display its default desktop theme.
I can only think that this is a completely unintended consequence of using a Microsoft account. Anyone?
You can choose what is synchronized between your devices from synch settings . If you don't want to synch desktop background you can turn off the Appearance slider. Hope this helps
Yeah, I had just spotted that Synchronised Themes had appeared in Desktop personalisation. I had better take a closer look to see what else may be being synced that I might not want.