It's odd you would need to disable UAC.
I have been using Win 10 from the first Technical Preview, through release, and now with the latest Tech Previews as well, and have installed and reinstall MC many. many times without needing to turn off UAC or unknown application prompts.
It prompts for the OK when I install an update, and that's it.
If you hate Win 10, you can always revert as well.