I can hear "ho-hum" and "not again" as I bring this up. My original intent on my Skylake system included dual-boot Win7/Win10 for various reasons, even though I'd become familiar with 10 on some other systems as part of the freebie upgrade.
I'm still thumping my chest in triumph over a troubled experience installing Creators #1703 under this dual-boot regime. I finally got it all sorted out, and Macrium Reflect was a lifesaver. So now, I have to wonder what I'm in for after mid-October.
I'm a Primo-Cache devotee and user, and some of the symptoms I'd experienced were common to other Primo users. Romex came out with a patch to address those concerns, but I sorted it out without the patch, and those other users weren't configured for dual-boot Win7/Win10.
I could have less luck this next time around . . . . I hope that another Creators build is not mandatory, or that I can anticipate avenues of options and steps to avoid the same misery as before.