diff --git a/src/ifcconvert/IfcConvert.cpp b/src/ifcconvert/IfcConvert.cpp
index 8f77d82ce3..cdb996e25a 100644
--- a/src/ifcconvert/IfcConvert.cpp
+++ b/src/ifcconvert/IfcConvert.cpp
@@ -378,12 +378,13 @@ int main(int argc, char** argv) {
 
 	GeometrySerializer* serializer;
 	if (output_extension == ".obj") {
-        const std::string mtl_temp_filename = change_extension(output_filename, "mtl") + TEMP_FILE_EXTENSION;
+        // Do not use temp file for MTL as it's such a small file.
+        const std::string mtl_filename = change_extension(output_filename, "mtl");
 		if (!use_world_coords) {
 			Logger::Message(Logger::LOG_NOTICE, "Using world coords when writing WaveFront OBJ files");
 			settings.set(IfcGeom::IteratorSettings::USE_WORLD_COORDS, true);
 		}
-		serializer = new WaveFrontOBJSerializer(output_temp_filename, mtl_temp_filename, settings);
+		serializer = new WaveFrontOBJSerializer(output_temp_filename, mtl_filename, settings);
 #ifdef WITH_OPENCOLLADA
 	} else if (output_extension == ".dae") {
 		serializer = new ColladaSerializer(output_temp_filename, settings);
@@ -514,12 +515,11 @@ int main(int argc, char** argv) {
 
 	delete serializer;
 
-    rename_file(output_temp_filename, output_filename);
-
-    if (output_extension == ".obj") {
-        std::string mtl_filename = change_extension(output_filename, "mtl");
-        std::string mtl_tmp_filename = mtl_filename + TEMP_FILE_EXTENSION;
-        rename_file(mtl_tmp_filename, mtl_filename);
+    // Renaming might fail (e.g. maybe the existing file was open in a viewer application)
+    // Do not remove the temp file as user can salvage the conversion result from it.
+    bool successful = rename_file(output_temp_filename, output_filename);
+    if (!successful) {
+        Logger::Message(Logger::LOG_ERROR, "Unable to write output file '" + output_filename + "");
     }
 
 	write_log();
@@ -531,7 +531,7 @@ int main(int argc, char** argv) {
     else
         printf("\nConversion took %d minute(s) %d seconds\n", seconds/60, seconds%60); // TODO Logger::Message(Logger::LOG_NOTICE, ...);
 
-	return 0;
+    return successful ? 0 : 1;
 }
 
 void write_log() {