It's probably something stupid, but its driving me nuts. I've been doing the following: 1. Open Boot Camp Assistant 2. Choose an ISO file of Windows 10 that I bought and downloaded from Microsoft. 3. Choose the size of the 2 partitions. 4. Click Install and it downloads the support software. 5. After doing that it auto-restarts. 6. I assume it's supposed to boot into Windows mode here, but instead it boots into the Mac partition again. 7. The BOOTCAMP partition doesn't have any data, and I can't find any way to continue the installation (i.e. restarting while holding Alt only shows the one partition). I've tried this a few times but it keeps doing this. It's especially annoying since it insists on downloading the support software on its own every time.