Sometimes books that CC finds when doing a wireless connect using its "scan on connect" option are are not in the calibre library or not correctly matched against books in calibre's library.
Case 1: CC found books that are not in calibre's library.
This might happen if you used some wireless service to purchase a book that was delivered directly to your device, in which case calibre doesn't know about the book. You can add the book to calibre's library while you are connected as a wireless device. Click on calibre's "Device" icon on the tool bar, find the book (it won't have "In Library" checked), right-click on the book and select "Add books to library". To avoid various problems with future book matching, it is best to switch to the library view and immediately send the book back to CC. This will tell CC the unique identifier that calibre gave the book, permitting CC and calibre to sync changes in the book's metadata.
Case 2: CC found books that are in calibre's library, but calibre does not mark the book as "On Device".
Book matching can fail even when the book is already in the calibre library. This can happen when the information inside the book (the "metadata") does not match the information in calibre. The most common cases involve titles being changed to contain series information and author names being changed from "Firstname LastName" to "Lastname, Firstname" or vice versa, sumetimes using plugboards. It also happens frequently with PDF and other formats that don't contain full calibre metadata.
There are two ways to repair the problem.
1) Resend the book from calibre. You will probably need to delete the unmatched copy from CC.
2) Manually tell calibre that a book on the device (CC) is the same as a book in the library, forcing a match. The steps are:
- Connect to calibre as a wireless device. Wait for metadata syncing to finish.
- Click on the Device icon in calibre to see the books on the device.
- Find books where the In Library column is empty. Sorting by In Library makes that easier to do.
- If an unmarked book is really in your calibre library, right-click on the book and select "Match book to library". A dialog box opens in which you can search for the correct book in the library. Find the book that is the match, then press OK. A "sync" icon will appear next to the book in the device view
- Repeat steps 3 and 4 as often as necessary.
- When finished, send the updated metadata to CC by clicking on the down arrow on the Device button and choosing "Update cached metadata on device".
Note that while connected to CC you can use "Update cached metadata on device" at other times, such as after you have updated metadata or covers for books in your library.