diff --git a/stg/dll/src/tif/TifImp.cpp b/stg/dll/src/tif/TifImp.cpp
index 98279be23..94c23debc 100644
--- a/stg/dll/src/tif/TifImp.cpp
+++ b/stg/dll/src/tif/TifImp.cpp
@@ -423,7 +423,7 @@ bool TifImp::OpenForWriteDirect(WeakStr name)
 {
 	GetWritePermission(name);
 
-	m_TiffHandle = TIFFOpen(ConvertDmsFileName(name).c_str(), "a");
+	m_TiffHandle = TIFFOpen(ConvertDmsFileName(name).c_str(), "w");
 	if (m_TiffHandle)
 		TIFFSetField(m_TiffHandle, TIFFTAG_SOFTWARE, "GeoDMS " BOOST_STRINGIZE( DMS_VERSION_MAJOR ) );
 	return m_TiffHandle;