C2512: No Appropriate Default Constructor Available

What It Means & How to Fix It

🧠 Why You’re Seeing This Error

C2512 means you’re trying to create an object without passing arguments, but the class or struct doesn’t have a default constructor (a constructor that takes no parameters).

In UE5, this usually happens when:

You try to construct an object by value with MyClass MyObj;, but the class only has constructors that require arguments
You’re working with custom structs or non-UObject classes
You forgot to define a default constructor when one is needed

💥 Example Error Message

error C2512: 'FMyStruct': no appropriate default constructor available

🛠️ Example Code

FMyStruct Data; // ❌ C2512: FMyStruct has no default constructor

But FMyStruct was only defined like this:

struct FMyStruct
{
    FMyStruct(int32 InValue) { ... } // ✅ But no default version
};

✅ How to Fix C2512 in UE5 – Step-by-Step

✔️ 1. Add a Default Constructor

Fix:

struct FMyStruct
{
    FMyStruct() {} // ✅ Now you can create it without arguments
    FMyStruct(int32 InValue) { ... }
};

✔️ 2. Avoid Creating Structs by Value If Not Needed

In UE5, it’s often safer to use pointers or references to avoid unnecessary constructor calls.

✔️ 3. Use the Available Constructor Properly

If a constructor exists that requires arguments — pass them.