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Troubleshooting Common YOLO Issues

YOLO Common Issues Image


This guide serves as a comprehensive aid for troubleshooting common issues encountered while working with YOLOv8 on your Ultralytics projects. Navigating through these issues can be a breeze with the right guidance, ensuring your projects remain on track without unnecessary delays.

Watch: Ultralytics YOLOv8 Common Issues | Installation Errors, Model Training Issues

Common Issues

Installation Errors

Installation errors can arise due to various reasons, such as incompatible versions, missing dependencies, or incorrect environment setups. First, check to make sure you are doing the following:

  • You're using Python 3.8 or later as recommended.

  • Ensure that you have the correct version of PyTorch (1.8 or later) installed.

  • Consider using virtual environments to avoid conflicts.

  • Follow the official installation guide step by step.

Additionally, here are some common installation issues users have encountered, along with their respective solutions:

  • Import Errors or Dependency Issues - If you're getting errors during the import of YOLOv8, or you're having issues related to dependencies, consider the following troubleshooting steps:

    • Fresh Installation: Sometimes, starting with a fresh installation can resolve unexpected issues. Especially with libraries like Ultralytics, where updates might introduce changes to the file tree structure or functionalities.

    • Update Regularly: Ensure you're using the latest version of the library. Older versions might not be compatible with recent updates, leading to potential conflicts or issues.

    • Check Dependencies: Verify that all required dependencies are correctly installed and are of the compatible versions.

    • Review Changes: If you initially cloned or installed an older version, be aware that significant updates might affect the library's structure or functionalities. Always refer to the official documentation or changelogs to understand any major changes.

    • Remember, keeping your libraries and dependencies up-to-date is crucial for a smooth and error-free experience.

  • Running YOLOv8 on GPU - If you're having trouble running YOLOv8 on GPU, consider the following troubleshooting steps:

    • Verify CUDA Compatibility and Installation: Ensure your GPU is CUDA compatible and that CUDA is correctly installed. Use the nvidia-smi command to check the status of your NVIDIA GPU and CUDA version.

    • Check PyTorch and CUDA Integration: Ensure PyTorch can utilize CUDA by running import torch; print(torch.cuda.is_available()) in a Python terminal. If it returns 'True', PyTorch is set up to use CUDA.

    • Environment Activation: Ensure you're in the correct environment where all necessary packages are installed.

    • Update Your Packages: Outdated packages might not be compatible with your GPU. Keep them updated.

    • Program Configuration: Check if the program or code specifies GPU usage. In YOLOv8, this might be in the settings or configuration.

Model Training Issues

This section will address common issues faced while training and their respective explanations and solutions.

Verification of Configuration Settings

Issue: You are unsure whether the configuration settings in the .yaml file are being applied correctly during model training.

Solution: The configuration settings in the .yaml file should be applied when using the model.train() function. To ensure that these settings are correctly applied, follow these steps:

  • Confirm that the path to your .yaml configuration file is correct.
  • Make sure you pass the path to your .yaml file as the data argument when calling model.train(), as shown below:
model.train(data="/path/to/your/data.yaml", batch=4)

Accelerating Training with Multiple GPUs

Issue: Training is slow on a single GPU, and you want to speed up the process using multiple GPUs.

Solution: Increasing the batch size can accelerate training, but it's essential to consider GPU memory capacity. To speed up training with multiple GPUs, follow these steps:

  • Ensure that you have multiple GPUs available.

  • Modify your .yaml configuration file to specify the number of GPUs to use, e.g., gpus: 4.

  • Increase the batch size accordingly to fully utilize the multiple GPUs without exceeding memory limits.

  • Modify your training command to utilize multiple GPUs:

# Adjust the batch size and other settings as needed to optimize training speed
model.train(data="/path/to/your/data.yaml", batch=32, multi_scale=True)

Continuous Monitoring Parameters

Issue: You want to know which parameters should be continuously monitored during training, apart from loss.

Solution: While loss is a crucial metric to monitor, it's also essential to track other metrics for model performance optimization. Some key metrics to monitor during training include:

  • Precision
  • Recall
  • Mean Average Precision (mAP)

You can access these metrics from the training logs or by using tools like TensorBoard or wandb for visualization. Implementing early stopping based on these metrics can help you achieve better results.

Tools for Tracking Training Progress

Issue: You are looking for recommendations on tools to track training progress.

Solution: To track and visualize training progress, you can consider using the following tools:

  • TensorBoard: TensorBoard is a popular choice for visualizing training metrics, including loss, accuracy, and more. You can integrate it with your YOLOv8 training process.
  • Comet: Comet provides an extensive toolkit for experiment tracking and comparison. It allows you to track metrics, hyperparameters, and even model weights. Integration with YOLO models is also straightforward, providing you with a complete overview of your experiment cycle.
  • Ultralytics HUB: Ultralytics HUB offers a specialized environment for tracking YOLO models, giving you a one-stop platform to manage metrics, datasets, and even collaborate with your team. Given its tailored focus on YOLO, it offers more customized tracking options.

Each of these tools offers its own set of advantages, so you may want to consider the specific needs of your project when making a choice.

How to Check if Training is Happening on the GPU

Issue: The 'device' value in the training logs is 'null,' and you're unsure if training is happening on the GPU.

Solution: The 'device' value being 'null' typically means that the training process is set to automatically use an available GPU, which is the default behavior. To ensure training occurs on a specific GPU, you can manually set the 'device' value to the GPU index (e.g., '0' for the first GPU) in your .yaml configuration file:

device: 0

This will explicitly assign the training process to the specified GPU. If you wish to train on the CPU, set 'device' to 'cpu'.

Keep an eye on the 'runs' folder for logs and metrics to monitor training progress effectively.

Key Considerations for Effective Model Training

Here are some things to keep in mind, if you are facing issues related to model training.

Dataset Format and Labels

  • Importance: The foundation of any machine learning model lies in the quality and format of the data it is trained on.

  • Recommendation: Ensure that your custom dataset and its associated labels adhere to the expected format. It's crucial to verify that annotations are accurate and of high quality. Incorrect or subpar annotations can derail the model's learning process, leading to unpredictable outcomes.

Model Convergence

  • Importance: Achieving model convergence ensures that the model has sufficiently learned from the training data.

  • Recommendation: When training a model 'from scratch', it's vital to ensure that the model reaches a satisfactory level of convergence. This might necessitate a longer training duration, with more epochs, compared to when you're fine-tuning an existing model.

Learning Rate and Batch Size

  • Importance: These hyperparameters play a pivotal role in determining how the model updates its weights during training.

  • Recommendation: Regularly evaluate if the chosen learning rate and batch size are optimal for your specific dataset. Parameters that are not in harmony with the dataset's characteristics can hinder the model's performance.

Class Distribution

  • Importance: The distribution of classes in your dataset can influence the model's prediction tendencies.

  • Recommendation: Regularly assess the distribution of classes within your dataset. If there's a class imbalance, there's a risk that the model will develop a bias towards the more prevalent class. This bias can be evident in the confusion matrix, where the model might predominantly predict the majority class.

Cross-Check with Pretrained Weights

  • Importance: Leveraging pretrained weights can provide a solid starting point for model training, especially when data is limited.

  • Recommendation: As a diagnostic step, consider training your model using the same data but initializing it with pretrained weights. If this approach yields a well-formed confusion matrix, it could suggest that the 'from scratch' model might require further training or adjustments.

This section will address common issues faced during model prediction.

Getting Bounding Box Predictions With Your YOLOv8 Custom Model

Issue: When running predictions with a custom YOLOv8 model, there are challenges with the format and visualization of the bounding box coordinates.


  • Coordinate Format: YOLOv8 provides bounding box coordinates in absolute pixel values. To convert these to relative coordinates (ranging from 0 to 1), you need to divide by the image dimensions. For example, let's say your image size is 640x640. Then you would do the following:
# Convert absolute coordinates to relative coordinates
x1 = x1 / 640  # Divide x-coordinates by image width
x2 = x2 / 640
y1 = y1 / 640  # Divide y-coordinates by image height
y2 = y2 / 640
  • File Name: To obtain the file name of the image you're predicting on, access the image file path directly from the result object within your prediction loop.

Filtering Objects in YOLOv8 Predictions

Issue: Facing issues with how to filter and display only specific objects in the prediction results when running YOLOv8 using the Ultralytics library.

Solution: To detect specific classes use the classes argument to specify the classes you want to include in the output. For instance, to detect only cars (assuming 'cars' have class index 2):

yolo task=detect mode=segment source='path/to/car.mp4' show=True classes=2

Understanding Precision Metrics in YOLOv8

Issue: Confusion regarding the difference between box precision, mask precision, and confusion matrix precision in YOLOv8.

Solution: Box precision measures the accuracy of predicted bounding boxes compared to the actual ground truth boxes using IoU (Intersection over Union) as the metric. Mask precision assesses the agreement between predicted segmentation masks and ground truth masks in pixel-wise object classification. Confusion matrix precision, on the other hand, focuses on overall classification accuracy across all classes and does not consider the geometric accuracy of predictions. It's important to note that a bounding box can be geometrically accurate (true positive) even if the class prediction is wrong, leading to differences between box precision and confusion matrix precision. These metrics evaluate distinct aspects of a model's performance, reflecting the need for different evaluation metrics in various tasks.

Extracting Object Dimensions in YOLOv8

Issue: Difficulty in retrieving the length and height of detected objects in YOLOv8, especially when multiple objects are detected in an image.

Solution: To retrieve the bounding box dimensions, first use the Ultralytics YOLOv8 model to predict objects in an image. Then, extract the width and height information of bounding boxes from the prediction results.

from ultralytics import YOLO

# Load a pre-trained YOLOv8 model
model = YOLO("")

# Specify the source image
source = ""

# Make predictions
results = model.predict(source, save=True, imgsz=320, conf=0.5)

# Extract bounding box dimensions
boxes = results[0].boxes.xywh.cpu()
for box in boxes:
    x, y, w, h = box
    print(f"Width of Box: {w}, Height of Box: {h}")

Deployment Challenges

GPU Deployment Issues

Issue: Deploying models in a multi-GPU environment can sometimes lead to unexpected behaviors like unexpected memory usage, inconsistent results across GPUs, etc.

Solution: Check for default GPU initialization. Some frameworks, like PyTorch, might initialize CUDA operations on a default GPU before transitioning to the designated GPUs. To bypass unexpected default initializations, specify the GPU directly during deployment and prediction. Then, use tools to monitor GPU utilization and memory usage to identify any anomalies in real-time. Also, ensure you're using the latest version of the framework or library.

Model Conversion/Exporting Issues

Issue: During the process of converting or exporting machine learning models to different formats or platforms, users might encounter errors or unexpected behaviors.


  • Compatibility Check: Ensure that you are using versions of libraries and frameworks that are compatible with each other. Mismatched versions can lead to unexpected errors during conversion.

  • Environment Reset: If you're using an interactive environment like Jupyter or Colab, consider restarting your environment after making significant changes or installations. A fresh start can sometimes resolve underlying issues.

  • Official Documentation: Always refer to the official documentation of the tool or library you are using for conversion. It often contains specific guidelines and best practices for model exporting.

  • Community Support: Check the library or framework's official repository for similar issues reported by other users. The maintainers or community might have provided solutions or workarounds in discussion threads.

  • Update Regularly: Ensure that you are using the latest version of the tool or library. Developers frequently release updates that fix known bugs or improve functionality.

  • Test Incrementally: Before performing a full conversion, test the process with a smaller model or dataset to identify potential issues early on.

Community and Support

Engaging with a community of like-minded individuals can significantly enhance your experience and success in working with YOLOv8. Below are some channels and resources you may find helpful.

Forums and Channels for Getting Help

GitHub Issues: The YOLOv8 repository on GitHub has an Issues tab where you can ask questions, report bugs, and suggest new features. The community and maintainers are active here, and it's a great place to get help with specific problems.

Ultralytics Discord Server: Ultralytics has a Discord server where you can interact with other users and the developers.

Official Documentation and Resources

Ultralytics YOLOv8 Docs: The official documentation provides a comprehensive overview of YOLOv8, along with guides on installation, usage, and troubleshooting.

These resources should provide a solid foundation for troubleshooting and improving your YOLOv8 projects, as well as connecting with others in the YOLOv8 community.


Troubleshooting is an integral part of any development process, and being equipped with the right knowledge can significantly reduce the time and effort spent in resolving issues. This guide aimed to address the most common challenges faced by users of the YOLOv8 model within the Ultralytics ecosystem. By understanding and addressing these common issues, you can ensure smoother project progress and achieve better results with your computer vision tasks.

Remember, the Ultralytics community is a valuable resource. Engaging with fellow developers and experts can provide additional insights and solutions that might not be covered in standard documentation. Always keep learning, experimenting, and sharing your experiences to contribute to the collective knowledge of the community.

Happy troubleshooting!

Created 2023-11-12, Updated 2024-06-02
Authors: glenn-jocher (5), RizwanMunawar (1)