Why I cannot open this upk files with UDK version 12264 which its error said something about "unrecognized data"

Hi ROOFFISH,

This is for Unreal Engine 4 development. For any questions relating to UDK can be posted on the UDK forums.

https://forums.epicgames.com/forums/366-UDK

Thanks, TJ

How to open this upk files? I installed the game called HAWKEN where it has upk files in C:\Program Files (x86)\Steam\SteamApps\common\Hawken\HawkenGame\CookedPCConsole.
I tried to open this upk files using UDK version 12264 by button “open an external package” in Content Browser window but then it can’t opened it.
The error said:
Load Errors
The following resources were not found. Any references to them were set to NULL.
WARNING: If you save now, these references will be saved as NULL.
Missing Files:
The file ‘C:\Program Files (x86)\Steam\SteamApps\common\Hawken\HawkenGame\CookedPCConsole\Bunker_Atmosphere.upk’ contains unrecognizable data, check that it is of the expected type.