langflow-ai/langflow · error · Error

An error occurred while uploading the file

Error message

An error occurred while uploading the file

What it means

404 from the is-installed check endpoint: the owner-scoped Folder lookup (id + user_id) found nothing before any config inspection happens. Identical semantics to the other project 404s — deleted, foreign, or mistyped project id.

Source

Thrown at src/frontend/src/hooks/files/use-upload-file.ts:113

            .split("/")
            .filter(Boolean)
            .pop();
          if (relativeParts.length > 0 && serverLeaf) {
            relativeParts[relativeParts.length - 1] = serverLeaf;
            setRelativePathForServerPath(res.path, relativeParts.join("/"));
          } else {
            setRelativePathForServerPath(res.path, file.webkitRelativePath);
          }
        }
        filesIds.push(res.path);
      }
      return filesIds;
    } catch (e: any) {
      const errorMessage =
        e?.response?.data?.detail ||
        e?.message ||
        "An error occurred while uploading the file";
      throw new Error(errorMessage);
    }
  };

  return uploadFile;
};

export default useUploadFile;

View on GitHub (pinned to 976ec789d2)

Solutions

  1. Refresh the project list and use the current project id.
  2. Confirm the authenticated user owns the folder.
  3. Re-open the project page so the SPA re-fetches ids.
Defensive patterns

Strategy: validation

Validate before calling

owned = {str(p.id) for p in await client.list_projects()}
assert str(project_id) in owned, "stale project id — refetch before install-check"

Try / catch

except httpx.HTTPStatusError as e:
    if e.response.status_code == 404:
        await refresh_project_ids()

Prevention

When it happens

Trigger: GET /api/v1/mcp/projects/{project_id}/install/check (status route) after the project was deleted, with a project id owned by another user, or with a stale id cached by the UI.

Common situations: UI page left open across a project deletion/recreation; account switch; copying project ids between instances.

Related errors

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/0d68881fb51babe1. Report an issue: GitHub.