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Accessed none error when trying to set blackboard value as vector

Hi

I am trying to make a simple waypoint system for my NPCs to move around. Basically I want my waypoint blueprint to set a blackboard key vector value for my NPC. However the key never gets set and I get this error log;

Error Blueprint Runtime Error: Accessed None trying to read property CallFunc_GetBlackboard_ReturnValue from function: ‘ExecuteUbergraph_Waypoint_Behavior_A’ from node: Set Value as Vector in graph: EventGraph in object: Waypoint_Behavior_A with description: Accessed None trying to read property CallFunc_GetBlackboard_ReturnValue

This is my waypoint blueprint;
93e647443ee91bfcb7bf15774256728ec999cb54.jpeg

This is my blackboard;
452e9b447c4ef51006dbf2f1ab5bc5efad7d1fcb.jpeg

And this is my behavior tree;
09c7c1413302823b6117497591935a2893bac4d3.jpeg

I have tried printing the Current Waypoint location to a string and that turned valid. So did the NPC Master character variable.

Any thoughts on what I am doing wrong? I also posted my question here in the answerhub but thought some people here might know what is going on Accessed none error when trying to set blackboard value as vector - UE4 AnswerHub

Thanks in advance :slight_smile:

Make sure all your variables aren’t nulls. Are you checking the waypoint somewhere? I’ve had this before and it almost always ends up being a null somewhere that the BT tries to reference. Make sure they’re updated before being called etc.