Select from menu Mazaika - Preferences.
On Mazaika Start
Start Blank - Start the program with blank page.
Open Last Library - Start program with blank page and open last used Library.
Open Last Project - Start program with last opened project.
Here you may switch render mode that you like to use:
Smart - Render of the mosaic beginning from the most essential parts of main theme image.
Random - Render of the mosaic in random order.
From Top To Bottom - Render from top left cell down to right bottom cell.