If you have never backed up your iPhone via iTunes, it will not let you back it up when it’s locked. In fact, iTunes won’t be able to even detect it.

So, how would you deal with this locked and disabled iPhone? Well, there is still a way to get rid of the issue. You will need to restore your device in Recovery Mode.
However, you’ll lose all of your data as it wipes out your apps, app data, contacts, photos, music and most of everything that resides on your iOS device.

If you’ve got iCloud sync and backup setup, the chances of finding all your app data, photos and contacts in iCloud are high. In that case, you can move ahead with the assurance that you can restore your iDevice from an iCloud backup and be up and run with almost everything.

If you had backed up your device using iTunes before…

If you had synced your device to iTunes, you are in luck. You can back up your iPhone and restore it as new without any issue.

>> Connect your iPhone to the computer and open iTunes.
>> Select the iPhone (from the sidepane or from top-right of the screen)
>> In the Summary tab, click on Back Up Now. Once your device is successfully backed up, click on Restore iPhone.
Note: If you have enabled Find My iPhone on your device, you won’t be allowed to restore it. Jump over here to turn off Find My iPhone remotely.

If iTunes proceeds with a problem-free restore, your device will be wiped clean and restored as a new device