diff --git a/libntfs-3g/unistr.c b/libntfs-3g/unistr.c
index 5854b3b7..db8ddf42 100644
--- a/libntfs-3g/unistr.c
+++ b/libntfs-3g/unistr.c
@@ -1189,8 +1189,9 @@ char *ntfs_uppercase_mbs(const char *low,
 			free(upp);
 			upp = (char*)NULL;
 			errno = EILSEQ;
+		} else {
+			*t = 0;
 		}
-		*t = 0;
 	}
 	return (upp);
 }