On one of my two PCs running Windows 10 10074 the Phone emulators did not have internet access, which is a bit of a hindrance if you want to write a demo that requires internet access, and after upgrading to VS2015RC from CTP6 I had an even bigger problem: the emulators did not even show up anymore. The only thing I saw was “Start”
I had inadvertently installed the Android Emulator, and there are apparently some issues with that. No amount of removing selected parts, repairing of modifying could fix it. So I went for the drastic solution: I uninstalled everything that remotely looked like it had something to do with VS2015RC, including the duplicate entry of the Windows Phone 8.1 emulators.
Then I opened the Hyper-V manager, removed all virtual machines there of Windows Phone 8.1 and 10 devicesAnd I deleted also all virtual switches. Now at one point the Hyper-V manager did not allow me to delete a virtual switch so I went for the bigger kill and removed all of Hyper-V by going into Programs and Features and uninstalling Hyper-V itself, and all the comes with it.
This requires the PC to reboot. After the reboot, I re-enabled Hyper-V again (which requires another reboot) and then I installed Visual Studio 2015RC again, sans the Android emulator and the cross-platform development kit, and then at last my Windows 10 emulators showed up – and they also now have internet access, albeit it takes them a minute to get it.
Your mileage may very, but this worked for me.