GitHub Actions fails with 'Error: Process completed with exit code 1' and no obvious cause. How do I find the real failing step and command?

Cause: "Process completed with exit code 1" is only the runner reporting that a shell command in a run step returned a non-zero status. The real reason is almost always printed earlier in that step's log (or in an earlier step whose failure was hidden). Run steps without an explicit shell use "bash -e", so the first failing command stops the step; with "shell: bash" the option pipefail is added, so a failure anywhere in a pipeline also fails the step. Fix: 1. Expand the failed step in the run log and read upward from the red line. The last lines before it are usually the tool's own error (test failure, linter, missing file, permission denied). 2. Re-run the job with debug logging (Re-run jobs > "Enable debug logging"), or set a repository secret or variable named ACTIONS_STEP_DEBUG to true. For runner-level detail set ACTIONS_RUNNER_DEBUG to true, which adds a runner-diagnostic-logs folder to the downloaded log archive. 3. Reproduce the exact command locally with the same shell options, for example "bash -e -o pipefail -c '<command>'", and with the same tool versions pinned in the workflow. 4. Check for a command in the middle of a pipeline or a command substitution that fails silently: add "set -x" at the top of the script to print each command, and split long pipelines so each stage's exit code is visible. 5. Look for steps marked continue-on-error: true earlier in the job; they can hide the first failure so a later step looks like the culprit. 6. If a matrix is used, fail-fast cancels sibling jobs when one fails; open the first red job, not the cancelled ones. Verify: the re-run log shows the underlying error text, and after fixing it the step exits 0 and the job turns green. Sources: https://docs.github.com/en/actions/how-tos/monitor-workflows/enable-debug-logging https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-syntax