How to Recover Lost Data From Android after Factory Reset?
Factory Reset means restoring a phone to factory setting, in which way you’ll wipe all data stored on the phone. Perhaps it is deemed to be an acceptable way to resurrect a phone when it comes to dealing with phone troubles, otherwise it would be a disaster to someone who accidentally performs factory reset on Android phone, especially in the situation that he/she didn’t back up the files previously. It is hard to recover data from Android phone without back-up. There isn’t an easy way, but still, it might be possible.
Actually, once the phone data gets lost, all you should do is immediately cease using the smartphone or set the phone into Flight mode in case that the deleted files get overwritten. The data will still be temporarily saved in a blank zone inside the phone after they are deleted. From then on, the more you use the phone, the more it overwrites the lost data. If the erased files are completely overwritten, they cannot be recovered any more. Make sure to not have any modifications/changes going on on your device, or at least as few as possible! Each change lowers your chances of a successful recovery.
Part 1: Restore Data from Backup
Nearly every Android phone is set with backup functions nowadays, provided that you backup files periodically, after factory reset you are allowed to get back synced data via “Settings” > “Back up & restore”, and select the latest backup file to restore.
Or you log in with the same Google account on your device which will restore some data from Cloud like Google Contacts, Calendar and, probably, settings for some apps. Plus, purchased apps are still available from Google Play, so you don't need to buy them again.
Afterwards, PLEASE do cultivate a habit of keeping copy of everything important on other device such as your PC and Cloud server. In the future, you might manage to avoid wiping your device but you can’t promise not to lose it or accidentally break it which likewise results in data loss. Backup is so important a thing to keep phone data.
Part 2: Retrieve data without Backup
As I said above, it is not easy to restore data without backup, but a recovery program may work for it.
General steps to check out:
1. Install and launch a data recovery software, freeware is better
Remember to enable debugging mode under Developer Option on your device, if your phone is with Android 4.4 or newer, you’ll find Developer Option missing, then you need to tap "Build number" 7 times > "Developer options" > "USB debugging". If it still fails to connect, you can check the USB cable and use another one.
3. Select files to to scan and recover
Note: The crucial key to recover data is "Backup", please try to do backup in daily life.