diff --git a/univention-ldb-modules/ucs-school-create_windows_computer b/univention-ldb-modules/ucs-school-create_windows_computer
index b731d18..d4a0fd4 100755
--- a/univention-ldb-modules/ucs-school-create_windows_computer
+++ b/univention-ldb-modules/ucs-school-create_windows_computer
@@ -1,6 +1,11 @@
 #!/bin/sh
+. /usr/share/ucs-school-lib/base.sh
+ou="$(school_ou)"
+if [ -z "$ou" ]; then
+	ou=$(school_ou "$(/usr/sbin/univention-config-registry get 'dhcpd/ldap/base')")
+fi
 samba4_addmachine=$(/usr/sbin/univention-config-registry get "samba4/addmachine")
 /usr/bin/test "$samba4_addmachine" = "deny" && exit 2
-/usr/sbin/umc-command "$@" || exit 1
+/usr/sbin/umc-command "$@" -o "school=$ou" || exit 1
 /usr/bin/test "$samba4_addmachine" = "dummy" && exit 3
 exit 0