Why does my iPhone 5S start blinking and locking up everytime I make or receive a phone call?
I cannot access any phone options and must use the on/off button to end the call?
This has been going on for several months.
iPhone 5s, iOS 10.1.1
Yes, setting the device back to factory settings will erase the phone, download a new version of the iOS via iTunes and install it onto your phone.
After that you'll be asked if you want to use an existing backup to restore your phone from, or set it up as a new device.
To rule out that damaged data from the backup are causing these problems, set it up as new device and test the call function. If it is working, restore from the last backup you made. If all apps are part of your media library on your computer, iTunes will install everything back onto your phone, apps and their settings included.
Check this article about backups as well and make sure to backup before you start.
About backups in iCloud and iTunes
If your screen is unresponsive shortly after a call, did you check if the proximity sensor on the top of the screen is not covered by a protective film or case?
Did you already restart the phone?
If a restart does not work, a force restart by holding the sleep and home button for about 10sec, until the Appel logo comes back, would be the next step before setting it back to factory settings.
Use iTunes to restore your iOS device to factory settings - Apple Support
I have restarted multiple times with no success. I turned off auto-brightness which was another suggestion. No success.
I have not tried a restore to factory settings. I want to understand the impacts of that first. Do I lose all settings, messages, contacts, notes, etc?
I reset to factory defaults, set up as a new phone and had the same result.
I updated to the latest OS level, 10.2, removed the case and screen protector, cleaned the screen, reset to factory defaults and had the same results. My conclusion is that the proximity sensor (hardware) is defective? I will taking it the Verizon store to see if it can be repaired and if not, will be forced to purchase a new phone since the warranty is long expired. Thanks for your help with this issue. I only wish I would have started down this path a couple of months ago when the problem first appeared.
Does a restore to factory defaults force me to re-install all of my apps?
Your'e welcome.
Yes, this looks like a defective proximity sensor, you did all that a user can do rot rule out a software issue.
All the best for your repair.
screen blinking during phone calls
