I've just bought my new xperia z today. It's fully charged now but there's a problem. After i unlock the lock screen the xperia z intro always shows up and restores the settings. I tried to fix it by restoring it to factory settings but it didn't fix it. Also it says that it's up to date. 
Please help!
PS: Also sometimes instead of the intro i get a blackscreen which goes away when i press the volume or power key
Just dial *#*#73556673#*#* to deactivate or activate the demo intro on your phone. Since you mention phone alway restore the settings by itself. I will suggest you to restore/repair your phone software via SUS http://www.sonymobile.com/gb/tools/update-service/ Hope this will solve your problem. Sorry for late reply 
I had an issue with the promotional video showing up when I locked and charged my phone, it was a simple fix once I got into he phone (it didn't reset any of my settings thank goodness) I went to Settings>Apps>All>Retail Demo and disabled it. No problem 
There was also another solution found in a previous thread. let me see if I can find it for you ~ Righty oh after some searching I believe it was typing in the above code while the phone is on charge. This has solved the issue for many people.
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