Unable to unlock mu phone after upgrade to marshmallow.

[AC Question]

I am Lenovo K4 Vibe Note. I got OS update recently and after update i am unable to unlock the phone.
Fingerprint sensor is not working and the unlock pattern too.
Even unable to launch cam from lock screen which used to work before update just by swiping on the screen from bottom right corner.
Please help me on this.

 

[belodion]

Use your alternative password to access the phone, or your Google account details when prompted, or try via Android Device Manager from another device.