diff --git a/harbour/source/rtl/filesys.c b/harbour/source/rtl/filesys.c
index ac5b141389..16ea8a7909 100644
--- a/harbour/source/rtl/filesys.c
+++ b/harbour/source/rtl/filesys.c
@@ -1303,7 +1303,7 @@ BOOL    hb_fsLock   ( FHANDLE hFileHandle, ULONG ulStart,
             break;
 
          case FL_UNLOCK:
-            bResult = ( _locking( hFileHandle, _LK_UNLOCK, ulLength ) == 0 );
+            bResult = ( _locking( hFileHandle, _LK_UNLCK, ulLength ) == 0 );
             break;
 
          default:
@@ -1882,4 +1882,4 @@ BOOL hb_fsEof( FHANDLE hFileHandle )
 #else
    return eof( hFileHandle ) != 0;
 #endif
-}
+}
\ No newline at end of file