I tried to install Windows 10 Tech Preview Build 10051 on my Lumia 520. It worked, but my phone would not recognize my SIM and the settings app was missing. I tried the Windows Phone Recovery Tool, but that didn't work, saying about halfway through installation it had lost connection with the phone, even though I had not done anything. I then erased and reset my phone through windowsphone.com, but that just set up Windows 10 for Phones again with a more features missing than before. There was no touch screen, just an all apps view, and many apps were missing. I tried the Windows Phone Recovery Tool multiple times after that, all with the same problem as before. My phone now only shows a red screen with the Nokia logo on it and is not recognized by my PC.