My Book has gone missing

[antiochus]

I have another external drive that I only plug into the computer when I back up my book, and then unplugg it when I have done the backup. All the material is still on that drive so I have not lost my book. Sorry I should have made that clearer. I am puzzled as to how it went missing on the other hard drive. I know I have not accidentally deleted it. However, last week I was hit by a ransom virus and some other data grabbing programs. They were successfully eliminated.

I'm handing over the computer to a technician tomorrow (it's midnight here at present). Maybe they can explain what has happened.