Sorry about the loss of your words, @np7675.
Sometimes–not always, but sometimes–PC or Scrivener crashes will corrupt the document that was open. Sounds like that’s what happened to you.
Having a better understanding of Scriv’s built-in backup system would be a good idea. If you continue to use Scrivener, I suggest you read this post I wrote a long while back on Backups. It was written for Scriv v1, but none of the backup features have changed except for menu options. You can skip the SYNCING section.
Also, it wouldn’t be a bad idea to crack open the Scriv user manual and have a look at section 5.2 “Backing Up Your Work” and Appendix B9 “Backup”. Only a few pages, and well worth your time.
Digesting this information will go a long way toward ensuring this doesn’t happen to you again.
Best,
Jim