Some files are missing after doing backup and factory reset on Android Lollipop I recently backed up and factory reset my Samsung Galaxy S5, stock and running Lollipop. All the apps that were previously on the device were re-installed and run fine, and the phone mostly performs as it is supposed to.

However, I have just realized that I have missing files; my daughter's telephone number is no longer listed in my contacts (found out the hard way trying to speed dial during an emergency as I was driving), and some music files are missing. By and large the phone was restored to its original settings and works just fine, it's just that there are a few but important to me files missing here and there.

Is there any way to identify and recover all missing files? There are probably more that I just haven't found missing yet.
Google backup is unreliable and won't back up everything, however it should be fairly easy to make a backup yourself next time.

You can use ADB to make a full backup. You'll need to install ADB first: on Linux sudo apt-get install adb usually works, on Windows you'll need to download it from somewhere.

Turn on USB debugging (in developer options, to access go to settings > about phone and tap build number 7 times) and connect to a computer via USB. Then open a terminal/console window and do adb devices to check the phone's connected, and then adb backup -all -f C:\backup.ab (where backup.ab is the absolute path to where you want it backed up from).

Source: http://forum.xda-developers.com/galaxy-nexus/general/guide-phone-backup-unlock-root-t1420351