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Run resumption is not supported inside a W&B sweep. If you pass a run_id or use wandb.init(resume=...) while a sweep agent is running, W&B ignores the run ID and starts a fresh run instead. You will see the following warning: 
wandb: WARNING Ignoring run_id 'YOUR_RUN_ID' when running a sweep.
This is expected behavior, not a bug. Sweep agents are designed to launch independent runs for each hyperparameter configuration. Resuming a specific run would conflict with the sweep controller’s job scheduling. Workarounds If you need fault tolerance for long sweep runs, consider these approaches:
  • Checkpoint and reload within a single run: Save model checkpoints at regular intervals inside your training function. On restart, load the latest checkpoint at the beginning of train(). The sweep starts a new run, but training picks up from the saved state.
  • Use --count 1 on SLURM with requeue: Submit each sweep agent job with wandb agent --count 1 SWEEP_ID. If the job is preempted, SLURM can requeue it and the sweep controller will assign a new configuration.
  • Mark a run as failed and requeue manually: If a run crashes mid-way, the sweep controller will eventually mark it as failed and may assign the same configuration to a new agent depending on your sweep settings.
If you need to continue an interrupted training job outside of a sweep, use wandb.init(resume="allow", id="YOUR_RUN_ID") in a standalone script instead. See Resume runs and Troubleshoot sweeps.
Sweeps Resuming