diff --git a/packaging/MSWindows/BUILD.sh b/packaging/MSWindows/BUILD.sh
index 0655a53b1b..d492224d0e 100644
--- a/packaging/MSWindows/BUILD.sh
+++ b/packaging/MSWindows/BUILD.sh
@@ -25,7 +25,7 @@ RUN_INSTALLER=${RUN_INSTALLER:-1}
 DO_MSI=${DO_MSI:-0}
 DO_SIGN=${DO_SIGN:-1}
 DO_TESTS=${DO_TESTS:-0}
-DO_SBOM=${DO_SBOM:1}
+DO_SBOM=${DO_SBOM:-1}
 
 # these are only enabled for "full" builds:
 DO_CUDA=${DO_CUDA:-$DO_FULL}