diff --git a/frontend/src/__tests__/unitTests/fileQueries.errorHandling.test.tsx b/frontend/src/__tests__/unitTests/fileQueries.errorHandling.test.tsx
new file mode 100644
index 00000000..c9a47a9b
--- /dev/null
+++ b/frontend/src/__tests__/unitTests/fileQueries.errorHandling.test.tsx
@@ -0,0 +1,103 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { renderHook, waitFor } from '@testing-library/react';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import useFileQuery from '../../queries/fileQueries';
+import * as utils from '@/utils';
+
+// Mock the utils module
+vi.mock('@/utils', async () => {
+  const actual = await vi.importActual('@/utils');
+  return {
+    ...actual,
+    sendFetchRequest: vi.fn(),
+    buildUrl: (path: string) => path, // Simple mock for buildUrl
+    makeMapKey: (type: string, name: string) => `${type}_${name}`
+  };
+});
+
+// Mock the context
+const mockZonesAndFspData = {
+  'fsp_test-fsp': {
+    name: 'test-fsp',
+    path: '/test/path',
+    type: 'posix'
+  }
+};
+
+vi.mock('@/contexts/ZonesAndFspMapContext', () => ({
+  useZoneAndFspMapContext: () => ({
+    zonesAndFspQuery: {
+      data: mockZonesAndFspData
+    }
+  })
+}));
+
+describe('useFileQuery 500 Error Reproduction', () => {
+  let queryClient: QueryClient;
+
+  beforeEach(() => {
+    queryClient = new QueryClient({
+      defaultOptions: {
+        queries: {
+          retry: false // Disable retries for faster tests
+        }
+      }
+    });
+    vi.clearAllMocks();
+  });
+
+  it('should handle 500 Internal Server Error correctly', async () => {
+    // Arrange
+    const fspName = 'test-fsp';
+    const folderName = '';
+
+    // Mock sendFetchRequest to return a 500 response with HTML body
+    // and a json() method that fails (as it tries to parse HTML)
+    const mockResponse = {
+      ok: false,
+      status: 500,
+      statusText: 'Internal Server Error',
+      json: async () => {
+        throw new SyntaxError('Unexpected token < in JSON at position 0');
+      }
+    };
+
+    vi.mocked(utils.sendFetchRequest).mockResolvedValue(
+      mockResponse as unknown as Response
+    );
+
+    // Act
+    const { result } = renderHook(() => useFileQuery(fspName, folderName), {
+      wrapper: ({ children }) => (
+        <QueryClientProvider client={queryClient}>
+          {children}
+        </QueryClientProvider>
+      )
+    });
+
+    // Assert
+    // We expect the query to eventually fail
+    await waitFor(() => expect(result.current.isError).toBe(true), {
+      timeout: 10000
+    });
+
+    // The bug is that it throws the SyntaxError from JSON parsing
+    // instead of the "Server returned 500" error.
+    // So this assertion confirms the BUG (on this branch)
+    // or confirms the FIX (if the message is clean).
+
+    // Since we want to REPRODUCE the failure, we check what it actually is.
+    // If the bug is present, the error message will be the SyntaxError.
+    // If the fix is present, it will be "Server returned 500 Internal Server Error".
+
+    const error = result.current.error;
+    console.log('Test caught error:', error?.message);
+
+    // We want to verify that the code *should* be handling this,
+    // so we Assert what we WANT (the fix).
+    // This test definition asserts the correct behavior.
+    // Running it on the buggy branch should FAIL this assertion.
+    expect(error?.message).toBe('Server returned 500 Internal Server Error');
+    expect(error?.message).not.toContain('Unexpected token');
+  });
+}, 15000);