diff --git a/virtualbox.spec b/virtualbox.spec
index cc2f9a6..97a9893 100644
--- a/virtualbox.spec
+++ b/virtualbox.spec
@@ -228,7 +228,9 @@ echo VBOX_WITH_VNC=1 >> Config.kmk
 #
 #  	VBOX_PATH_PACKAGE_DOCS set propper path for link to pdf in .desktop file 
 # 	VBOX_WITH_REGISTRATION_REQUEST= VBOX_WITH_UPDATE_REQUEST= just disable some functionality in gui 
+#       -j1 disable parallel build to avoid "Out of memory: Kill process" crash of build in buildservice
 /usr/bin/kmk \
+        -j1 \
 	KBUILD_VERBOSE=2 \
 	VBOX_WITH_REGISTRATION_REQUEST= VBOX_WITH_UPDATE_REQUEST= \
 	TOOL_YASM_AS=yasm \