Mine came with Windows 10 preinstalled and works fine. However, Windows wants to update itself and there is not enough space avaialbe on the internal storage to do it.
I have tired using a USB hard drive. I have tried using SD cards. It does not give me the option to select either one.
At some point there will likely be a security issue or W10 will no longer support my device. There must be a work-a-round for this.