What causes "Project not found" in n8n-io/n8n?

Verify the project exists and the caller has access: `GET /projects/ `.

Project not found

Error message

Project not found

What it means

HTTP 404 with literal body 'Project not found' sent at folder.controller.ts:53 by the `validateProjectExists` middleware when `projectService.getProject(projectId)` throws (project missing or inaccessible in the current tenant). The middleware short-circuits with `res.status(404).send('Project not found')` before the route handler runs.

Source

Thrown at packages/cli/src/controllers/folder.controller.ts:53

export class ProjectController {
	constructor(
		private readonly folderService: FolderService,
		private readonly enterpriseWorkflowService: EnterpriseWorkflowService,
		private readonly projectService: ProjectService,
	) {}

	@Middleware()
	async validateProjectExists(
		req: AuthenticatedRequest<{ projectId: string }>,
		res: Response,
		next: NextFunction,
	) {
		try {
			const { projectId } = req.params;
			await this.projectService.getProject(projectId);
			next();
		} catch (e) {
			res.status(404).send('Project not found');
			return;
		}
	}

	@Post('/')
	@ProjectScope('folder:create')
	@Licensed('feat:folders')
	async createFolder(
		req: AuthenticatedRequest<{ projectId: string }>,
		_res: Response,
		@Body payload: CreateFolderDto,
	) {
		const { projectId } = req.params;

		try {
			const folder = await this.folderService.createFolder(payload, projectId);
			return folder;
		} catch (e) {

View on GitHub (pinned to 5ac6606e81)

Solutions

Verify the project exists and the caller has access: `GET /projects/<projectId>`.
Refresh the parent project list in the UI and re-issue the folder request against a valid ID.
Audit for deleted projects whose IDs still appear in client state/bookmarks.

Defensive patterns

Strategy: validation

Validate before calling

async function projectExists(svc: ProjectService, id: string) {
  try { await svc.getProject(id); return true; } catch { return false; }
}
// gate folder calls on projectExists(...)

Try / catch

const r = await fetch(`/projects/${pid}/folders`);
if (r.status === 404) { /* refresh project list, re-issue with valid pid */ }

Prevention

Cache the current project list and invalidate on project delete.
Validate :projectId at the client before any folder action.
Surface 404 'Project not found' as 'project was deleted' rather than a hard error.

When it happens

Trigger: Any folder route under a `:projectId` path where the project doesn't exist, was deleted, or isn't visible to the caller's scope. The middleware runs before `@ProjectScope` enforcement completes the lookup.

Common situations: Stale project ID in a bookmarked URL; project deleted between page load and folder action; cross-tenant access attempts; typos in manually constructed URLs.

Related errors

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/cc4276844ee75ddb. Report an issue: GitHub.