[keat]

Just this afternoon, when I try to do anything on my 5800, it says use keyguard switch to unlock screen and keys. I slide the keyguard switch, it says the same.

I also have a snall key icon at the top of the screen.

I've tried a 5 minute battery pull.

Any other suggestions??

[keat · Accepted solution]

OK.. I did a full reset.. Red, Green & camera, and now I can get back in.

Any ideas what caused this ??

[gabra]

I encountered with the same problem after a (succesful) firmware update. I was unable to use a hard reset thought and had to return back to previous version of my firmware.
I was able to update firmware to 20 but not to any later (the last is 51).

[rahmz]

the key guard also strucks and only way is to remove back cover to disconnect battery and restart!!

this is really bad nokia is resposible to give some reply and also let the users who are purcahsing costly smart phones to depend not to suffer at times we are in hurry.

[tjmtjmtjm]

This morning this problem hit my 5800: while I was reading some articles on wifi the phone locked and it wouldn't unlock whatever I do. When I press shut off button it says to use key guard unlock but it won't work.

I have latest firmware, memory is not full and there aren't lot of applications.

I tried with removing battery, sim, sd card, waiting: nothing helped.

I already thought about factory reset of full blown hard reset.

Then I read post about headphones so I tried this and phone was unlocked and free. (I actualu didn't use headphones but just 3,5mm jack.)

With unlocked phone I went to "Menu/Settings/Phone/Phone mgmt./Auto. keyguard." and chandeg value from "None" to "User defined" of 5min. Then I restarted phone. When I turned it back on it was unlocked! Then I returned value to None and phone is still ok.

Just for any case I will make back up of phone and set USB cable to be in default PcSuite mode to easily make backup if this happens again.

Thanks everyone for posting and hope this will help others.