diff --git a/share/mk/local.meta.sys.mk b/share/mk/local.meta.sys.mk
index a7e1016a5637..0e985b0b20f8 100644
--- a/share/mk/local.meta.sys.mk
+++ b/share/mk/local.meta.sys.mk
@@ -10,7 +10,7 @@ MK_INSTALL_AS_USER= yes
 _default_makeobjdir=$${.CURDIR:S,^$${SRCTOP},$${OBJTOP},}
 
 .if empty(OBJROOT) || ${.MAKE.LEVEL} == 0
-.if defined(MAKEOBJDIRPREFIX)
+.if defined(MAKEOBJDIRPREFIX) && !empty(MAKEOBJDIRPREFIX)
 # put things approximately where they want
 OBJROOT:=${MAKEOBJDIRPREFIX}${SRCTOP}/
 MAKEOBJDIRPREFIX=