If the iOS 11 developer beta hangs, freezes, or just won't install properly on your iPhone, it might be your SIM card.
I tried half a dozen time to install the iOS 11 developer beta on my iPhone and it froze up every time. I finally figured out the culprit and am here to save you some time and hassle if it happens to you.
Here's the situation: I downloaded the iOS 11 developer beta software profile onto my iPhone successfully. I downloaded iOS 11 successfully. When my iPhone restarted so I could finish the setup process, everything froze.
I put my iPhone into Recovery mode, restored it to its factory settings, and reverted back to iOS 10. I tried again, this time, directly from iTunes. The same thing happened.
I restored my iPhone through Recovery Mode (because that's the only way to get it to a position where I could do anything at all with it, including turning it off). Then sent it into DFU mode and tried again. Same.
I restored my iPhone back to factory settings and tried installing the iOS 11 developer beta from Apple Configurator 2. Same.
I restored my iPhone back to factory settings and tried installing via iTunes on a different computer. Same.
I switched the unused SIM card in my iPhone 7 Plus for the Verizon SIM card I was using for my daily use iPhone and tried again. Guess what? It worked!
I switched them back: My iPhone SE (daily use iPhone) got the in-use Verizon SIM card back, while my iPhone 7 Plus (beta tester) got the unused SIM card back. Guess what? Frozen. That means I can't keep my unused SIM card in my iPhone 7 Plus. No problem. I don't need it.
I put my iPhone into Recovery Mode again so I could get to a position where I could turn it off and remove the unused SIM card (don't laugh, I did this for you) and then removed the SIM card. I tried again. Guess what! It worked!
That's right, without a SIM card at all, my iPhone 7 Plus will run the iOS 11 developer beta. I just can't take it out of Wi-Fi range. Not a problem for me. My daily use iPhone is the one that needs a SIM card, not my beta tester.
Thank goodness my issue was resolved after much testing and trial and error. Hopefully, you're reading this before you've tried installing the developer beta half a dozen times, too.
I'm not suggesting that all SIM cards are tweaking out with the iOS 11 developer beta. All of my iMore cohorts were able to download and install the developer beta on a variety of different devices, new and old, without any problems. This appears to be a somewhat isolated issue.
I'm also not suggesting that, if your iPhone froze while trying to install the beta it is definitely the SIM card. I'm just saying this might be the problem. It could actually be any number of problems. This is merely one solution you could try.
So, if you find yourself with an iPhone that is frozen before you even make it through the setup process, try removing the SIM card to see if that works. Keep in mind, however, that you probably won't be able to use that SIM card with that iPhone with the iOS 11 developer beta, so you'd better have another daily-use iPhone in your possession.
If you're having some other issues with your iPhone after installing the iOS 11 developer beta, check out our troubleshooting guides.