I'm trying to reset/update my iPhone 8, but I keep getting an "unknown error 10" and the process doesn't complete.
iPhone 8
See this support document for update/restore errors and troubleshooting steps. iOS update and restore errors - Apple Support
See this support document for update/restore errors and troubleshooting steps. iOS update and restore errors - Apple Support
My iMac is running Sierra (due to some software that I need to use that isn't happy under newer OS's), and I never could get the restore to work. I ended up resetting/reinstalling the phone using my wife's computer, running Catalina. Then, when I connected the iPhone to my computer to restore from a backup, the phone wouldn't show up in iTunes. I was able to get it to show up again, using the software indicated in this article: https://osxdaily.com/2019/11/06/fix-iphone-11-not-showing-syncing-itunes-mac/. Then, I was able to restore using the backup I made prior to resetting the phone. I am now up and running and life is good again.
error 10
