What causes "failed to attach to exec: %w" in nektos/act?

Check the wrapped Docker error; the exec instance may have been removed or the container stopped.

failed to attach to exec: %w

Error message

failed to attach to exec: %w

What it means

Error "failed to attach to exec: %w" thrown in nektos/act.

Source

Thrown at pkg/container/docker_run.go:598

resp, err := cr.cli.ExecAttach(ctx, idResp.ID, client.ExecAttachOptions{
	TTY: isTerminal,
})
if err != nil {
	return fmt.Errorf("failed to attach to exec: %w", err)
}
defer resp.Close()

View on GitHub (pinned to 4f41128141)

Solutions

Check the wrapped Docker error; the exec instance may have been removed or the container stopped.
Retry the run; transient daemon errors can interrupt attach.

When it happens

Trigger: Thrown at pkg/container/docker_run.go:598 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nektos/act@4f41128141 (2026-08-15). Data as JSON: /api/errors/e0cbb0f1c959c464. Report an issue: GitHub.