I downloaded the nightly build: audacity-win-rc9422aa-2.1.3-alpha-08-jul-16.zip and it does not open Audacity with the cannot find any audio devices message.
Alpha builds are only for testers, or if you cannot get 2.1.2 release to find devices.
If you are saying that 2.1.3-alpha cannot find audio devices, what make and model number of computer do you have? If you upgraded it from previous Windows. you need to go to the computer manufacturer’s web site to see if there are Windows 10 audio drivers for your computer model. See Missing features - Audacity Support.
2.1.3-alpha does not create devices for you if Windows does not see any. After you have updated to Windows 10 audio drivers as above, I suggest you look in Windows Sound and follow the instructions in that link to show and enable all your devices. That is always worth doing because even with good drivers, often not all the devices are enabled by default.
Gale