diff --git a/src/softIoc/Makefile b/src/softIoc/Makefile
index 11fecd3b3..80989a450 100644
--- a/src/softIoc/Makefile
+++ b/src/softIoc/Makefile
@@ -32,7 +32,7 @@ softMain$(OBJ) : epicsInstallDir.h
 
 epicsInstallDir.h:
 	$(ECHO) "FINAL_LOCATION=$(FINAL_LOCATION)"
-	$(PERL) ../makeInstallDir.pl $(FINAL_LOCATION) > $@
+	$(PERL) ../makeInstallDir.pl '$(FINAL_LOCATION)' > $@
 
 clean::
 	@$(RM) epicsInstallDir.h