Currently, some iOS users have to complain that Touch ID completely disappeared from App Store purchase menus on the iPhone, even though it was enabled in iPhone main settings after upgrade to iOS 8.3. Here how to fix Touch ID not working for App Store purchase after iOS 8.3 upgrade. Below steps also work for iPhone 5s, iPhone 6, iPhone 6 Plus and iPad Air 2.
- Launch Settings menu on iPhone or iPad running iOS 8.3
- Tap on Touch ID & Passcode
- Enter the Passcode
- Toggle iTunes & App Store to OFF
- Press the Home button to return to the Home screen.
- Reboot
- Enter the Passcode on the Lock screen
- Relaunch the Settings menu on iPhone or iPad
- Tap on Touch ID & Passcode
- Enter the Passcode
- Toggle iTunes & App Store to ON