# 0064: Mission label not found

The compiler can't find the starting [label](https://docs.sannybuilder.com/language/data-types#labels) of a mission.

**Possible solutions:** make sure that each mission declared in the header exists in the source file. Either add a missed mission, or remove the declaration:

```
DEFINE MISSIONS 1
DEFINE MISSION 0 AT @MISSION_0

:MAIN

// error, MISSION_0 not found 
```