pin lock suddenly appeared

[hanpan]

Hi, I have an xperia tablet which has worked fine since bought last october. I went to use it a few weeks ago now.It has always been set to 'swipe to unlock' but now it is asking for a pin code, which I did not set up. And now I am locked out!

I have searched the inrternet but any tips about holding down volume and power button just don't work and I cannot find anything else.

For added info the only app it has on there outsde of the standard ones is bittorrent.

As a last ditch I hooked it up to my mac this evening where it says there is a new software update available, but I first need to charge the tablet to 80% before it will install. Interestingly it connected up to the computer while the tablet was technically 'locked' still.

Help please. Rather peeved at not having a useable tablet...!

Thanks!

[Uliwooly]

Do you have an antivirus app? 

[hanpan]

Nope. Now you say that it seems rather obvious that I should... I always thought of it more like a phone than a computer (not that it has a sim)

[Uliwooly]

well, it could be a 

SIM lock 

or

a Pin lock (settings > security > lock > pin lock)

or 

it could be an antivirus app

[takrzem]

or it could be enforced security settings as a result of adding corporate mail account that requires these