What It Means & How to Fix It in UE5
🧠 Why You’re Seeing This Error
This error means you’re trying to call a function on a reference that hasn’t been set — in other words, the variable is None (null), and Unreal doesn’t know what to run the function on.
In UE5 Blueprints, this usually happens when:
- A variable was never assigned before calling a function on it
- An actor was destroyed or not yet spawned
- You’re referencing something that only exists on the server/client, but you’re on the wrong side
- You forgot to validate the object before calling the function
💥 Example Error Message
Blueprint Runtime Error: "Accessed None trying to call function 'GetHealth'" on variable 'EnemyRef'
🛠️ Common Blueprint Scenario
[Event BeginPlay]
→ Get (EnemyRef)
→ Call Function: GetHealth
But EnemyRef is None — the actor wasn’t assigned yet.
Unreal throws the runtime error and stops the function call.
✅ How to Fix It in UE5 – Step-by-Step
✔️ 1. Use an IsValid Check Before Calling the Function
[IsValid(EnemyRef)]
├── True → Call Function: GetHealth
└── False → Print String: "EnemyRef is None"
Never call a function on an object unless you’ve confirmed it’s valid.
✔️ 2. Make Sure the Variable Is Assigned Properly
[Event BeginPlay]
→ Get All Actors Of Class: BP_Enemy
→ Get (0)
→ Set (EnemyRef)
Or use:
On Actor Spawned → Store reference to EnemyRef
✔️ 3. Avoid Calling Too Early (e.g., in Construction Script or Before Spawn)
Some objects don’t exist yet at certain stages. Use:
- BeginPlay (for runtime logic)
- Delays (if needed for sequencing)
✔️ 4. Double-Check Networking Context (Optional)
If the reference only exists on the server:
- Run logic on the server
- Or use a RepNotify / RPC to sync with client
✅ Summary: How to Fix “Cannot Call Function on a None Object” in UE5
| Cause | Fix Example |
|---|---|
| Variable is None (null) | Validate it with IsValid() before calling function |
| Object never assigned | Assign the variable during BeginPlay or actor spawn |
| Actor destroyed or not yet spawned | Delay logic or ensure correct event ordering |
| Server/client mismatch | Use replication-safe patterns if referencing networked actors |
