why i cant change my screen lock.

[Cheng]

[Uliwooly]

that's odd, set a pattern lock > then remove it > restart your phone and try again.

Also make sure that you do NOT have any of this apps

task killers

task managers

antivirus

battery apps

ram apps

booster apps

remember if you another lockscreen app it might be creating this issue.

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[Cheng]

thank you

[Uliwooly]

if you still have issues, you could always repair your phone

Update Service (SUS)

http://www.sonymobile.com/gb/tools/update-service/

http://www-support-downloads.sonymobile.com/Software%20Downloads/Update_Service_Setup-2.11.12.5.exe

PC Companion (PCC)

Bridge (for Mac)

Alternatives on How to backup Xperias

http://talk.sonymobile.com/thread/36355

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[Cheng]

but how can i remove the pattern lock... i have set a one already and each time i click on it, it ask me to set one again

[Uliwooly]

that's quite odd, do you have a SIM lock? if you do remove it, if nothing works, then backup your phone and repair it with SUS

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[Cheng]

OMG... it now lock my phone and i need to get PUK code, what can i do .... i bought this phone from the sony website.

[Uliwooly]

in some countries even SIM free phones are network locked, PUK codes are only for Carriers/networks, so you have contact them to unlock your phone

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[Cheng]

the sim network company?

[HussainQuadri]

I think you need to deactivate any andministrator apps (Settings - Security - Device Administrators - untick all).

Oh and hold down power and volume up button for ten seconds, remove SIM then reboot to get pass SIM lock.