Phone stuck on padlock with spinning circle

[AC Question]

I was taking pictures then phone restarted, and it asks for the pin which i input in, then it says verifying and the states "starting android", then it comes onto this padlock which then turns into an open padlock but then get a spinning circle, i've left this for hours and nothing happens afterwards. I tried doing soft reset but just brings me to enter the pin and then the whole thing happens. I then tried putting it in recovery mode, so i pressed home, power and volume down key and then pressed volume up to continue and it gets stuck at ODIN mode with downloading, do not turn off target.

I can't even get to the data to back up or i cant even get to the options to factory reset it. What is the open padlock with the colourful spinning circles, and how do i get around this problem?

 

[belodion]

Try a Cache Partition wipe. You don't mention the phone, but here it is for the S6: http://forums.androidcentral.com/showthread.php?t=551809