[Starson17]

Originally Posted by Giuseppe Chillem

1) I have restart Calibre without reinstalling.

Good. I've never needed to reinstall (and I can't recall any crashes either, not that I disbelieve you.)

2) I have sorted the library by date and they were not there.

I was suggesting you use your OS file browser to look directly in the folder set as the Calibre Library folder. It should have your books. I have no idea why they don't show up in Calibre.

3) I know the time is there but I want to see it.

I understood that.

It will solve once and for all the problem of multiple batch of books added the same day. In the actual scenario I can't recognize where one batch end and where another starts.

I have no trouble identifying the breaks. The gap in time is much larger. I view this info in an SQL Browser when I want it.

4) Can't understand why the precise adding time is better for you than the batch adding time (one and for all). The former doesn't give us any usefull information, the latter let us identify the latest batch.

I don't see how you can identify the batch if you don't see the time. I can identify both, but I have to use the SQL browser. I've occasionally needed to know how long it takes to add files. I can get that from the exact time during a batch add.

5) File Hash + Duplicate tag is the complete solution for any problem. When a duplicate file hash is found you have 99.99999999% chance you have a duplicate.

True, but not finding a duplicate doesn't mean you don't have any duplicates, and I'm almost always looking for duplicates, not 99.99999999% duplicates. Tiny changes in the file mean that I wouldn't get a match with file hash/CRC. It's just not a tool I need. If I did need it, I'd use a third party file dupe finder. I'm not saying you don't need/want it.

The final solution is:

File Hash duplicate check -> Ask for deletion.

I keep certain 100% duplicates I don't want deleted. Specifically, If I want 2 different copies of a particular format, I usually copy the record, with all formats, then change only the one format.

believe me when I say this solves the Calibre Crash problem that generates duplicates.

I've never had a duplicate due to a "Calibre Crash."

If the TAG library crashes and you have 100 "unknown - Unknown" books the tag mechanism won't work while the hash mechanism will find 100% of them, either checking against existing books or if you restart the batch, against new added books.

I don't fully understand this. If you are getting a crash using tags, you should report it. I've never seen one. I have lots of "Unknown" authors, but they are truly unknown and they aren't duplicates very often. IIRC from your earlier posts, you are seeing "Unknown" because you have metadata pulled from inside the file, and the internal metadata isn't there, or it's poor. I can understand in that case that you want hash-based duplicate detection, as your metadata is so poor, but it's just not something that I would ever use. My books almost always have some identifying author or title information in the filename to work with.