Going back to a clean and working Windows 10 Technical Preview for Phones
1. Go to Settings > System > About > Reset my device
2. Accept the first warning
3. accept the second warning
4. The phone will restart and the spinning wheels will appear. They might be running for some minutes without any
apparent progress but be patient and shortly the white bar will start to fill the centre of the screen
5. After the spinning wheels finish their job the phone will restart automatically then you will see “Nokia” and a black
5.1 At this point some old models were with the black screen light on for a while until power was pressed and quickly a
“Not for resale” message in red with a Windows Logo will appear.
6. Later, after tapping power softly if the phone stopped responding, or after waiting patiently, a “Welcome” screen with
white background to choose the language should appear.
7. Complete the information requested and when you get to your Microsoft account enter the same account that you
used to have in your phone.
8. Microsoft will ask you to be tracked and some other question but then the glorious “Restore phone” option will appear.
Select the phone that you want to restore and click “next”
9. A screen confirming the restoring should appear and around 17% it might stop and a screen showing “Verify your
identity” will appear.
10. If the screen appear, use the alternative email and another device to get the validation code and tap “next” and it
should continue (this time a bit more slowly).
11. The restore will finish and either you will get a message letting you know that not everything was restored or you
might get one that says that everything is fine click “OK”
11.1 If you have had accounts to check the email you might see a screen “Restored accounts” and you will need to enter
the password again and click “next”
11.2 In some occasions (Lumia 520 and Lumia 625) Windows 10 TP just died here (at “Restored accounts”) and tapping
next didn't have any effect!. After tapping and waiting enough it was necessary to press and hold power to switch off the
phone, wait until it was off and switch it on again. By doing this the phone entered into an infinite loop until it finally went
back to its traditional black and shown “Welcome back”
12. The screen “Almost done…” will appear asking to use the data connection. I chose “No” and then it went to the
screen “Thank you for using Nokia”