The deadlock issue shows itself by making the game freeze. Eventually, you will be given the option to close Project Zomboid and you will have to restart the game. This have only been observed to happen when attacking a npc that is already attacking, so it is relatively rare. It is still recommended to use this deadlock patch to fix this issue. To my knowledge, this doesn't affect normal gameplay in any way.

1. Open your Project Zomboid directory (In Steam, right-click on Project Zomboid and select "Manage"->"Browse local files"
   
2. Go to the mod directory: Steam\steamapps\workshop\content\108600\3335447777\mods\KnoxEventExpanded\media\java\client
   
3. NOTE: Default directory should be: C:\Program Files (x86)\Steam\steamapps\workshop\content\108600\3335447777\mods\KnoxEventExpanded\media\java\client
   
4. Copy the "zombie" directory to your Project Zomboid directory (Default: C:\Program Files (x86)\Steam\steamapps\common\ProjectZomboid). It should give you a dialogue to replace two files.
   
5. Start the game

1. In Steam, right-click on Project Zomboid and select "Properties"
   
2. In the properties window, go to the "Installed Files" tab
   
3. Press "Verify integrity of game files"
   
4. Steam will now check all files and remove the fix by redownloading the modified files

Picture of NPC Overlay[i.imgur.com]

1. NPC Overlay - all your npcs, their current task and subtask will be shown here. Right-clicking will bring up a context menu to give them orders.
   
2. Loot window - Use this to set which loot categories the npcs should look for by left-clicking each respective category. White means enabled, red means disabled.
   
3. NPC stance towards other players and npcs - Either passive i.e. they will defend themselves or attack npcs/players that are already hostile, while aggressive means they will attack anyone they see. Left click the panel or press the "comma"-key (English keyboard layout) to toggle on/off
   
4. NPC fight/retreat - Either fight i.e. they will fight all zombies they see or retreat i.e. they will ignore all zombies. Useful for getting away from a sticky situation. Left click the panel or press the "period"-key (English keyboard layout) to toggle on/off.