This has been happening to me once in a while on my MacBook. I have a bunch of sermon notes in a User Tool. I was working with it this morning and when I try to update it says "the book "Eb" cannot be found" and will not update. A week ago I lost a hour of notes when this happened. I hit command W to save and exit and it was some other strange "book" it couldn't find then.
What is going on?