Calibre-Kindle-Mac Mystery

[HenrysAxe]

Several months ago I sought assistance for what I thought was a problem with Calibre updates causing all titles and info on the device to be wiped clean. As there didn't seem to be any type of solution I continued to use the software and did not experience further issues. Last night I added ten titles via Calibre to the Kindle Paperwhite. As it was late, I decided to wait until this morning to send them to the Kindle. When I opened Calibre the entire slate of information was gone, all titles that were there since February - gone; all the left side column info numbers - gone - reset to zero. I am guessing my original idea that the disappearance of info was somehow related to updates was not valid. My question becomes - can anyone out there offer an explanation for these mysterious happenings? I'm using the latest Calibre update (1.28.0) OS X Mountain Lion on a MacBrook Pro and Kindle Paperwhite (second release) I thank you in advance for any tech advice you can offer.

[eschwartz]

http://manual.calibre-ebook.com/faq....n-app-is-blank

Originally Posted by @calibre manual

In order to understand why that happened, you have to understand what a calibre library is. At the most basic level, a calibre library is just a folder. Whenever you add a book to calibre, that book’s files are copied into this folder (arranged into sub folders by author and title). Inside the calibre library folder, at the top level, you will see a file called metadata.db. This file is where calibre stores the metadata like title/author/rating/tags etc. for every book in your calibre library. The list of books that calibre displays is created by reading the contents of this metadata.db file.

There can be two reasons why calibre is showing a empty list of books:

• Your calibre library folder changed its location. This can happen if it was on an external disk and the drive letter for that disk changed. Or if you accidentally moved the folder. In this case, calibre cannot find its library and so starts up with an empty library instead. To remedy this, do a right-click on the calibre icon in the calibre toolbar and select Switch/create library. Click the little blue icon to select the new location of your calibre library and click OK.
• Your metadata.db file was deleted/corrupted. In this case, you can ask calibre to rebuild the metadata.db from its backups. Right click the calibre icon in the calibre toolbar and select Library maintenance->Restore database. calibre will automatically rebuild metadata.db.

[HenrysAxe]

Thanks very much - one of the most thorough explanations I've ever received on any forum I've ever joined. Much appreciated.

[eschwartz]

The credit is all due to Kovid, he provides the best support for any consumer application I've ever heard of. Bugfixes are often fixed in hours, for example.