[HanaShiratori]

Unfortunately working on a local machine with or without infrequent saves always carries a certain risk of data loss, since your computer could crash at any time due to power issues, disk failure or any other pc component dying or just a software bug like in the described case (but who knows, maybe the real reason was a hardware defect). Either use features like auto save which should minimize the risk of creating corrupted save files or work on a network drive (or the cloud) with file versioning enabled and optimally frequent, incremental snapshots / backups. But it's important to frequently save your file, otherwise you will increase the risk of data loss. And be aware, that working on a local machine is dangerous in itself - if you have to do that frequently however (no network connection), use external storage (small usb thumb sticks) for at least providing some kind of backup.

Fortunately I learned this lesson as a kid playing countless hours of RPGs where forgetting to save frequently lead to replaying hours of gameplay again... ;)