Ultralytics v8.4.62 Released
Summary
We’ve released Ultralytics v8.4.62, a high-value reliability update focused on one of the most important parts of training: making sure your trained models are actually saved ![]()
The headline fix prevents successful training runs from ending without checkpoints due to EMA NaN/Inf issues during save checks, especially in some AdamW + AMP workflows. This release also includes a substantial Ultralytics Platform docs refresh, improved test stability, cleaner external documentation links, and leaner CI.
If you train Ultralytics YOLO models regularly, this is a strongly recommended upgrade ![]()
Key Highlights
Major training fix: checkpoints are no longer discarded
The most important change in this release comes from PR #24731 by @glenn-jocher, with author profile @glenn-jocher.
This fixes a bug where valid training runs could complete successfully but still fail to save any checkpoint.
This was especially relevant for some setups using AdamW + AMP, where validation could corrupt live EMA weights and trigger repeated warnings like Skipping checkpoint save... EMA contains NaN/Inf.
Safer validation during AMP training
With the fix in PR #24731 by @glenn-jocher, validation still benefits from mixed precision speedups, but it no longer permanently modifies or “poisons” the live EMA model.
That means:
- validation no longer mutates the live EMA in place
- finiteness checks now happen on the original
fp32EMA - overflow is safely clamped during checkpoint serialization instead of skipping the save
New coverage for overflow-safe checkpoint saving
This release also adds test coverage to ensure models with large-but-finite EMA weights are still saved correctly, helping protect against regressions in future updates.
Documentation Improvements
Big Ultralytics Platform docs refresh
The documentation update in PR #24726 by @glenn-jocher, from @glenn-jocher, significantly improves accuracy and API coverage across the Ultralytics Platform documentation.
Highlights include:
- corrected UI labels and workflows
- expanded Platform API reference
- clearer docs for datasets, annotations, training, deployment, billing, teams, and integrations
- newly documented API capabilities such as dataset embeddings, class management, GPU availability, and import flows
If you use the Ultralytics Platform, this should make day-to-day workflows much easier to follow ![]()
Fixed broken COCO evaluation links
In PR #24723 by @glenn-jocher, from @glenn-jocher, outdated COCO evaluation links were replaced with the canonical COCO upload instructions, and old docs author profile links were corrected.
Improvements and Maintenance
Less flaky data-related tests
PR #24724 by @glenn-jocher, authored by @glenn-jocher, reduces unnecessary downloads in tests and reuses cached assets when possible.
This should improve CI dependability and reduce false failures.
Leaner CI workflows
Two updates helped streamline CI:
- PR #24725 by @glenn-jocher, from @glenn-jocher, reduces git clone size and speeds up docs publishing and selected test workflows
- PR #24722 by @UltralyticsAssistant, from @UltralyticsAssistant, updates the Codecov GitHub Action from
v6tov7
Why this release matters
Ultralytics v8.4.62 is not a major model-feature release, but it is a very important stability release ![]()
It helps by:
- preventing trained YOLO models from being lost at the end of training
- improving confidence in AMP-based training workflows
- reducing wasted compute from failed checkpoint saves
- making Platform docs more accurate and easier to use
- improving internal test and CI reliability
If you’ve ever seen a run finish well but end with no checkpoint saved, this release directly addresses that issue.
What’s Changed
- Fix broken COCO eval server and docs author links by @glenn-jocher
- Bump
codecov/codecov-actionfromv6tov7by @UltralyticsAssistant - Fix flaky data asset tests by @glenn-jocher
- Slim CI git clones: blobless docs publish, shallow Conda tests, drop unused checkout by @glenn-jocher
- Improve Platform docs accuracy and API coverage by @glenn-jocher
- Prevent NaN/Inf EMA from discarding training checkpoints by @glenn-jocher
You can also review the full changelog for v8.4.62 or browse the release page for v8.4.62.
Try it out
We recommend upgrading and giving it a spin, especially if you train with AMP or AdamW:
pip install -U ultralytics
If you’re starting a new project, we recommend Ultralytics YOLO26 for the best current performance and end-to-end support across detect, segment, classify, pose, and OBB.
Feedback
Please try v8.4.62 and let us know how it works for your training and deployment workflows. Feedback, bug reports, and regression checks are always appreciated — they help us keep YOLO reliable for everyone.