I updated my Z5 to Marshmallow 6.0 yesterday. Worst mistake of my life.

It locked out my phone and wiped some SD photos (so I couldn't get past the keylock screen - on entering the correct code, it goes black momentarily, thinks about it, then returns to the lock screen on a never ending loop). Clicking any notifications fro the dropdown menu brings up the keylock screen again, and on inputting the correct keycode in, I get the error message 'unfortunately, system UI has stopped working' then it returns to the locked screen again.

I can receive calls, emails and texts...but I cannot access them, or send anything.

Worth noting that I already did a factory reset (and lost further photos from my sons 5th birthday), which fixed the problem last night...and this morning it return in the same manner as above.

About to do a further factory reset, but that's no way to live my life with a 3 month old phone....

Someone please help (And also any help on recovering my SD images would be welcomed!)

I have been to x2 O2 stores, with one Guru who couldn't' find a solution.


  • 2
    How did you factory reset the device? Did it successfully complete? If yes, then what is the current problem? I can't believe that the device would be asking for some credentials at lock screen even after a factory reset. Are you now seeing a screen where you are asked to enter your Google account credentials?
    – Firelord
    Commented Mar 18, 2016 at 16:19
  • Just a small suggestion. Do a factory reset and disable lock screen temporarily. Means till time you get a proper solution/next OTA update. Also do many wrong unlocks attempts purposely, then after 3rd attempt it should ask for your google credentials.That might solve any problems related to unlocking.
    – Iftekhar
    Commented Mar 26, 2016 at 4:53

2 Answers 2


When this type of problem happens (I've seen it happen more than once where the unlock code stops working). Go to Google's Android Management and change the code. This has cured the problem twice for my clients.

There are a number of ways to get to Google's Device Manager. One ways is:

http://play.google.com -> Click on the Gear icon at the top right corner of the screen -> Click on Android Device Manager -> Login -> Select your target phone (if you have multiple devices) -> click on Lock. Follow the prompts to change/set your lock code.

So far this has worked to resolve the issue. I'm not sure if something specifically has to be done to enable this feature, but since you are experiencing problems, you might consider testing the steps when you're not experiencing the immediate problem so that you can verify that it will be available the next time next time you need it.


You mentioned that your device is the Z5. I assume that your device is the one mentioned below:

Sony Xperia Z5

I did a quick search, and found that they are supposed to be releasing an update that fixes the issue:

Sony Forums and Tech Support

Now, in reference to the Photos. I am also assuming that the photos are saved on the phone's internal SD Card, and not a removable external card. If this is so, can you connect to the phone via USB/ADB? This could allow you to retrieve the photos, if it works. In order for ADB to work, you would need to have USB debugging enabled. In order for USB to work, you need the proper device drivers installed on your computer. When connecting the phone to the computer, you should be able to access the phone's internal SD Card (but not the system partition). That should allow you to copy the photos over.

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