# behavior error ,behavior error
**URL:** https://discussions.unity.com/t/behavior-error-behavior-error/199642
**Category:** Questions & Answers
**Created:** [December 3, 2017, 9:42pm UTC](https://discussions.unity.com/t/behavior-error-behavior-error/199642 "2017-12-03T21:42:15Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Kira4220](https://discussions.unity.com/u/Kira4220)
#### Post date: [December 3, 2017, 9:42pm UTC](https://discussions.unity.com/t/behavior-error-behavior-error/199642/1 "2017-12-03T21:42:15Z")
I’m using c sharp the error reads as No MonoBehavior scripts in the file, or their names do no match the file name.
using UnityEngine;
public class PlayerMovement : MonoBehaviour {
```
public Rigidbody rb;
// Update is called once per frame
void FixedUpdate ()
{
rb.AddForce (0, 0, 2000 * Time.deltaTime);
}
```
},
after trying to apply my script in unity i receive this error
The associated script can not be be loaded. Please fix any compile errors and assign a valid script.
also another error
No Mono Behavior scripts in the file, or their names do not match the file name.
I’m writing in c sharp on Mono Develop
using UnityEngine;
public class PlayerMovement : MonoBehaviour {
```
public Rigidbody rb;
void FixedUpdate ()
{
rb.AddForce (0, 0, 2000 * Time.deltaTime);
}
```
}
---
### Author:  [@jdean300](https://discussions.unity.com/u/jdean300)
#### Post date: [December 3, 2017, 10:06pm UTC](https://discussions.unity.com/t/behavior-error-behavior-error/199642/2 "2017-12-03T22:06:04Z")
MonoBehaviours must be in a file of the same name - so the file holding this PlayerMovement class must be named PlayerMovement.cs