missing archive

good morning, in 2016 I installed this program on my pc, and saved all the emails of my work email address. In December of 2017 I also saved all the emails of my pec. Today, after a year and a half, I need to review some old emails, and then I access the program, but the entire archive has disappeared. I must point out that I have never reset the PC, I have never changed the hard disk, I have never uninstalled the program. How is it possible that everything has disappeared? Is there an expiration date for data storage? Is it possible to recover all the data in some way? Please help me

there is no expiration date for the data storage.
You can do a Restore from a Backup to get your MailStore archive back.