On Windows 10 Mobile there is a trick: http://forums.windowscentral.com/wi...ing-wrong-device-password-too-many-times.html
For Windows Phone 8.1 and lower:
Sometimes this is a glitch.
Often times it is from too many invalid PIN attempts.
Regardless, the solution is the same. Hard Reset.
Power off the phone > hold Volume Down > press Power > keep holding Volume Down until you see the exclamation (!
) screen, then immediately release the Volume Down
Now tap Volume Up / Volume Down / Power / Volume Down
You should see the spinning gears and your phone will reflash the last OS version held in recovery. You do loose data, but get your phone back. Sign into your Microsoft Account and restore your backup during the set up.
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