Troubleshooting Vue.js applications can be a daunting task, especially when you encounter errors that don't give much information about what went wrong or how to fix it. However, with the right debugging tools and techniques, you can quickly identify and solve many common problems. Here are some of the most common Vue.js errors and their solutions:

1. "TypeError: Cannot read property 'name' of undefined"

   This error happens when a v-bind directive is missing its value or when the object that the variable represents doesn't exist. To fix this, make sure that you have properly defined your data and that your variables are correctly referenced in your template.

<template>
    <div :title="user.name">Hello {{ user.name }}</div>
</template>

<script>
export default {
  data() {
    return {
        user: null // or {}
    }
  }
};
</script>

2. "Error in v-bind directive: Invalid expression."

   This error occurs when there's a syntax error in your v-bind expression. To fix this, make sure that you have properly written the expression inside the brackets and that it is correctly referenced in your data or methods.

<template>
    <div :title="user.fullName">Hello {{ user.name }}</div>
</template>

<script>
export default {
  data() {
    return {
        user: { name: 'John', lastName: 'Doe' }
    }
  },
  computed: {
    fullName() {
      return this.name + ' ' + this.lastName;
    }
  }
};
</script>

3. "Error in v-model directive: Invalid expression."

   This error happens when there's a syntax error in your v-model expression. To fix this, make sure that you have properly written the expression inside the brackets and that it is correctly referenced in your data or methods.

<template>
    <input type="text" v-model="user.name">
</template>

<script>
export default {
  data() {
    return {
        user: { name: 'John' }
    }
  }
};
</script>

4. "Error in component definition: "

   this error happens when there's a syntax error in your component definition or if the component is not properly registered. To fix this, make sure that you have properly defined your component and that it has been correctly imported and used in other components.

<template>
    <my-component></my-component>
</template>

<script>
import MyComponent from './MyComponent.vue'

export default {
  components: {
    MyComponent
  }
};
</script>

5. "Uncaught ReferenceError: Vue is not defined"

   This error happens when there's a problem with the order of your script files or if you forgot to import Vue before using it in your code. To fix this, make sure that you have properly imported Vue and that you are not trying to use it before its definition.

<script src="https://cdn.jsdelivr.net/npm/vue@2"></script>

<script>
new Vue({
  el: '#app',
  data: {
    message: 'Hello World!'
  }
});
</script>

These are some of the most common Vue.js errors and their solutions, but there may be many more depending on your specific problem. Always remember to test your code in different environments and with various data to ensure that it works as expected.