n8n-io/n8n · error

Failed to load existing workflow

Error message

Failed to load existing workflow ${workflowId} to preserve webhook IDs: ${message}

What it means

ensureWebhookIds attempted to load the existing workflow to carry webhookIds over by node name (keeping URLs stable across rebuilds), but the load threw. The failure is surfaced with the underlying message so the caller knows IDs could not be preserved rather than being silently regenerated.

Solutions

  1. Confirm the workflow id exists and the service can read it
  2. Retry after fixing the underlying load error so webhook IDs can be reconciled
Defensive patterns

Strategy: try-catch

When it happens

Trigger: Thrown at packages/@n8n/instance-ai/src/tools/workflows/workflow-json-utils.ts:153 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/b27e557c65cd3b45. Report an issue: GitHub.

Appendix: source

Thrown at packages/@n8n/instance-ai/src/tools/workflows/workflow-json-utils.ts:153

 * For updates, preserve existing webhookIds by node name so URLs remain stable.
 */
export async function ensureWebhookIds(
	json: WorkflowJSON,
	workflowId: string | undefined,
	ctx: InstanceAiContext,
): Promise<void> {
	const existingWebhookIds = new Map<string, string>();
	if (workflowId) {
		try {
			const existing = await ctx.workflowService.getAsWorkflowJSON(workflowId);
			for (const node of existing.nodes ?? []) {
				if (node.webhookId && node.name) {
					existingWebhookIds.set(node.name, node.webhookId);
				}
			}
		} catch (error) {
			const message = error instanceof Error ? error.message : String(error);
			throw new Error(
				`Failed to load existing workflow ${workflowId} to preserve webhook IDs: ${message}`,
				{ cause: error },
			);
		}
	}

	for (const node of json.nodes ?? []) {
		if (WEBHOOK_NODE_TYPES.has(node.type) && !node.webhookId) {
			node.webhookId = (node.name && existingWebhookIds.get(node.name)) ?? randomUUID();
		}
	}
}

/**
 * For updates, preserve existing node-group IDs by group name. The sandbox SDK
 * build has no view of the saved workflow, so toJSON() mints a fresh deterministic
 * ID for every group — overwriting the stable ID of a group the user created in
 * the editor. Reconciling by name here keeps it stable, mirroring ensureWebhookIds.

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