diff --git a/examples/compiler/01_data_regions.ipynb b/examples/compiler/01_data_regions.ipynb
index a2b9016dbd..c0cf5a5330 100644
--- a/examples/compiler/01_data_regions.ipynb
+++ b/examples/compiler/01_data_regions.ipynb
@@ -491,6 +491,7 @@
    ],
    "source": [
     "u_pad = TimeFunction(name='u_pad', grid=grid, space_order=2, padding=(0,2,2))\n",
+    "u_pad._data_allocated[:] = 0\n",
     "u_pad.data_with_halo[:] = 1\n",
     "u_pad.data[:] = 2\n",
     "equation = Eq(u_pad.forward, u_pad + 2)\n",