PDF Reader Pro for Windows supports AutoSave feature that can save your files automatically within few seconds as you work. However, Auto Save should be enabled manually rather than by default.
Follow the instructions below to turn Auto Save on:
1. Run PDF Reader Pro -> Go to Home screen;
2. Click Settings in the sidebar;
3. In the General tab, you will see Auto Save that is currently off at the bottom;
4. Click the Auto Save toggle to switch Off to On, and now the Auto Save feature is enabled.