I had this same exact issue. Here's what I did to resolve it:
1. Remove the mouse from your list of Bluetooth devices if it was added
2. Choose to add a Bluetooth device
3. Right-Click on the Magic Mouse and choose Properties (or Settings)
4. Choose services, and put a checkmark in the empty box (It usually takes a few seconds to show up)
5. Close the properties window and let Windows install the drivers
I could personally never get Windows to connect to the device without following these steps. Hopefully it works for you!