[Sony Xperia M4 Aqua] chrissphillips88:
Xperia Z3+ Lockdown solved

I had this exact same issue, after i replaced the screen on my phone it gave me 30 seconds after every reboot before the lockdown screen kicked in, even when i entered my google account credentials it said incorrect username and/or password - they were correct, my xperia website and various confirmation emails from when i set it up could confirm that. i spent two days and finally unlocked it.

this was my process:

1) step one was because i was able to use the device for up to thirty seconds-ish i could attempt to change settings, however when i went to settings-security-my xperia protect it would take too long to load the screen for me to deactivate. SO.....i restarted, then went to settings, then reset to factory condition.

2)obviously because this feature is for theft protection a factory reset wont solve the issue, you still get the lockdown screen after 30-40 seconds. Instead after the reset when you begin to set the phone up new, literally skip all parts of the set up process, tap the bottom left corner like a mad man and skip everything until you get to the phone's desktop. This process simply clears all data from the device "including the previous My Xperia Protection account info". By the time you get to the phones desktop the lockdown screen will have kicked in; reboot again.

3)after another reboot, you will be at the phones desktop screen like usual, with 30-40 seconds free, swipe down and tap the user icon from the settings tray, then add user. you should have enough time to throw a random user name in their like john smith or something. once into the new user account you will notice the lockdown screen doesn't kick in, im guessing since the guest user is pretty useless anyways and has no permission to phone, text, reset, or change settings. BUT.........what it does do, is give you time to input your google account to the play store app and allow the device a chance to remember the email in the keyboard shortcut menu!! this will save precious time in a later step. Again Reboot

4)After another reboot you will be back to the main account's desktop and have 30-40 seconds before lockdown, now as fast as possible swipe down and hit settings, then go to security, then hit protected by my xperia, then hit activate, YUPP we are going to activate this feature again, despite the fact its already active. when it asks for your google email, use the shortcut on the keyboard which the phone should be recommending from when we typed it last, then throw in your password and hit done. The lockdown screen will most likely kick in by now so reboot.

5)its worth checking the My Xperia site to confirm your device was added and also check your Gmail to see the confirmation email that the phone is protected. Now when the phone reaches desktop again for what feels like the millionth time, again quickly swipe down, hit settings, security, protected by My Xperia, then hit deactivate, then input your details again. If you were quck enough you will have gotten the security feature to shut down and no more lockdown.

I can confirm this worked for me and i have done all the updates since then, installed all my old apps and done dozens of reboots with no more lockdown screen.

---------- Post added at 11:59 PM ---------- Previous post was at 11:56 PM ----------

Similar, when i logged onto the "My Xperia" website it just said cant find any devices, like none had even been linked, despite having a confirmation email from 2015 i must never had finished the set up.

I had this exact same issue, after i replaced the screen on my phone it gave me 30 seconds after every reboot before the lockdown screen kicked in, even when i entered my google account credentials it said incorrect username and/or password - they were correct, my xperia website and various confirmation emails from when i set it up could confirm that. i spent two days and finally unlocked it.

this was my process:

1) step one was because i was able to use the device for up to thirty seconds-ish i could attempt to change settings, however when i went to settings-security-my xperia protect it would take too long to load the screen for me to deactivate. SO.....i restarted, then went to settings, then reset to factory condition.

2)obviously because this feature is for theft protection a factory reset wont solve the issue, you still get the lockdown screen after 30-40 seconds. Instead after the reset when you begin to set the phone up new, literally skip all parts of the set up process, tap the bottom left corner like a mad man and skip everything until you get to the phone's desktop. This process simply clears all data from the device "including the previous My Xperia Protection account info". By the time you get to the phones desktop the lockdown screen will have kicked in; reboot again.

3)after another reboot, you will be at the phones desktop screen like usual, with 30-40 seconds free, swipe down and tap the user icon from the settings tray, then add user. you should have enough time to throw a random user name in their like john smith or something. once into the new user account you will notice the lockdown screen doesn't kick in, im guessing since the guest user is pretty useless anyways and has no permission to phone, text, reset, or change settings. BUT.........what it does do, is give you time to input your google account to the play store app and allow the device a chance to remember the email in the keyboard shortcut menu!! this will save precious time in a later step. Again Reboot

4)After another reboot you will be back to the main account's desktop and have 30-40 seconds before lockdown, now as fast as possible swipe down and hit settings, then go to security, then hit protected by my xperia, then hit activate, YUPP we are going to activate this feature again, despite the fact its already active. when it asks for your google email, use the shortcut on the keyboard which the phone should be recommending from when we typed it last, then throw in your password and hit done. The lockdown screen will most likely kick in by now so reboot.

5)its worth checking the My Xperia site to confirm your device was added and also check your Gmail to see the confirmation email that the phone is protected. Now when the phone reaches desktop again for what feels like the millionth time, again quickly swipe down, hit settings, security, protected by My Xperia, then hit deactivate, then input your details again. If you were quck enough you will have gotten the security feature to shut down and no more lockdown.

I can confirm this worked for me and i have done all the updates since then, installed all my old apps and done dozens of reboots with no more lockdown screen.