diff --git a/configure b/configure
index 70c3474784..46433975ca 100755
--- a/configure
+++ b/configure
@@ -28676,7 +28676,7 @@ fi
 
 if test "${PBX_FREETDS}" != "0";
 then
-    case `grep TDS_VERSION_NO ${FREETDS_DIR:-/usr/include}/tdsver.h` in
+    case `grep TDS_VERSION_NO ${FREETDS_DIR:-/usr}/include/tdsver.h` in
 	*0.64*)
 		FREETDS_INCLUDE="${FREETDS_INCLUDE} -DFREETDS_0_64"
 	;;
diff --git a/configure.ac b/configure.ac
index 2b5cee0dd5..f8927357b7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -784,7 +784,7 @@ AST_EXT_LIB_CHECK([OPENSSL], [ssl], [ssl2_connect], [openssl/ssl.h], [-lcrypto])
 AST_EXT_LIB_CHECK([FREETDS], [tds], [tds_version], [tds.h])
 if test "${PBX_FREETDS}" != "0";
 then
-    case `grep TDS_VERSION_NO ${FREETDS_DIR:-/usr/include}/tdsver.h` in
+    case `grep TDS_VERSION_NO ${FREETDS_DIR:-/usr}/include/tdsver.h` in
 	*0.64*)
 		FREETDS_INCLUDE="${FREETDS_INCLUDE} -DFREETDS_0_64"
 	;;