Share your experience!
Solved! Go to Solution.
Force shutdown your device:
Try again.
Boot the phone in safe mode and see if you can change it like that::
http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008
thanks anyway
Thank you so much, it worked! :smileysmileythumbsup:
Cool.