Do you have enough free space on your drives where Hand2Note and the database are stored? That may be causing the issue.
Also make sure that your Windows user has full admin rights and that you're running H2N as admin at all times. If the problem still occurs, please reinstall Hand2Note with deleting the database:
You will be able to restore your hands from archive folders or you can try and export some hands from Reports menu before deleting H2N