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

Confirm the container is running before exec; check the wrapped Docker error for details.

failed to create exec: %w

Error message

failed to create exec: %w

What it means

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

Source

Thrown at pkg/container/docker_run.go:591

idResp, err := cr.cli.ExecCreate(ctx, cr.id, client.ExecCreateOptions{
	User:         user,
	Cmd:          cmd,
	WorkingDir:   wd,
	Env:          envList,
	TTY:          isTerminal,
	AttachStderr: true,
	AttachStdout: true,
})
if err != nil {
	return fmt.Errorf("failed to create exec: %w", err)
}

View on GitHub (pinned to 4f41128141)

Solutions

Confirm the container is running before exec; check the wrapped Docker error for details.
Verify the exec command exists inside the container image.
Ensure the Docker daemon has resources available to create the exec instance.

When it happens

Trigger: Thrown at pkg/container/docker_run.go:591 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/4f1914241bf080bf. Report an issue: GitHub.