diff --git a/qsirecon/workflows/recon/anatomical.py b/qsirecon/workflows/recon/anatomical.py
index 46bbe7f0..97e8f17f 100644
--- a/qsirecon/workflows/recon/anatomical.py
+++ b/qsirecon/workflows/recon/anatomical.py
@@ -137,6 +137,7 @@ def init_highres_recon_anatomical_wf(
                 seg="hsvs",
                 space="T1w",
                 suffix="probseg",
+                extension=".nii.gz",
                 compress=True,
             ),
             name="ds_qsiprep_5tt_hsvs",