diff --git a/cfg/microsoft_sal.cfg b/cfg/microsoft_sal.cfg
index 3cdb8299cd4..36371a3610b 100644
--- a/cfg/microsoft_sal.cfg
+++ b/cfg/microsoft_sal.cfg
@@ -338,7 +338,6 @@
   <define name="__blocksOn(resource)" value=""/>
   <define name="__callback" value=""/>
   <define name="__checkReturn" value=""/>
-  <define name="__format_string" value=""/>
   <define name="__in_awcount(expr,size)" value=""/>
   <define name="__nullnullterminated" value=""/>
   <define name="__nullterminated" value=""/>
diff --git a/test/testlibrary.cpp b/test/testlibrary.cpp
index 1bdc06f5182..75e461d6389 100644
--- a/test/testlibrary.cpp
+++ b/test/testlibrary.cpp
@@ -1072,6 +1072,10 @@ class TestLibrary : public TestFixture {
             const Settings s = settingsBuilder().library("std.cfg").library("gnu.cfg").library("bsd.cfg").build();
             ASSERT_EQUALS(s.library.defines.empty(), false);
         }
+        {
+            const Settings s = settingsBuilder().library("std.cfg").library("microsoft_sal.cfg").build();
+            ASSERT_EQUALS(s.library.defines.empty(), false);
+        }
     }
 };