Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
How To Fix The iOS 8.0.1 Error On Your iDevice
One of the biggest bugs in the iOS 8.0.1 was an error that stopped you from calling out, sending text messages and using the Touch ID feature.
We wont go into much detail and will instead give you the basics on how to fix the ios 8.0.1 error.
By downloading the final build of iOS 8 as it was released as an IPSW file, you can restore your iPhone to the latest stable version.
How to fix the iOS 8.0.1 Error on Your Device :
1. Visit This Website or…
2. Directly download the file if your using an iPhone 6 CLICK HERE
3. Directly download the file if your using an iPhone 6 Plus CLICK HERE
and open iTunes. Select under the backup options “this computer,” then hit “Back Up Now.” This takes a full snapshot of your contacts, email, apps and settings, and stores it on your computer.
5. On iTunes in Windows, hold down the Shift key and click the Restore option. Next, select your iPhone’s IPSW file and follow the prompts.
6. Those of you on OS X, hold down Alt key and click the Restore option in iTunes. Next, select your iPhone’s IPSW file and follow the prompts.
7. Wait for the IPSW to unload on your iPhone. You may need to disable “Find my iPhone” first, found in your iCloud settings. Once your iPhone has been restored to iOS 8, your iPhone will be wiped clean. All you have to do now is restore the backup from iTunes.
8. Click “Restore backup,” select the latest backup you just performed, and wait for the process to complete.
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