Thank you, davidfor, for taking the time to give me such a detailed explanation.
Here's some more information based on the points you made.
For books with Adobe DRM, the device needs to be authorized. -- The Glo is authorized with the same Adobe ID as my computer. I've checked this and have also unauthorized the Glo and even the computer and then reauthorized them several times. That often allows me to transfer a book successfully, but the problem will reoccur.
When you hit the reset, the database isn't saved and an old version is used when the device is restarted. If there are any problems with the database, these can show up at this time. -- Interesting, I've also done power off/on and didn't realize there was a difference.
Are you a calibre user? If so, I recommend using my Kobo Utilities plugin to do a check of the database. -- Yes, I do use Calibre and I did check the DB using your plugin and it said the DB was OK.
The only other thing I can think of, and would be consistent with the restart fixing problems, is that the Adobe host service on the device is crashing. If this has crashed or otherwise returns an error, then the error and the black cover makes sense. Restarting the device would restart the service and solve this problem. -- Hmmm. That seems to be the best theory so far.
The only thing I can think of that might cause this is a bad book. -- This seems unlikely given that I get the "unauthorized" message on every book I transfer until a reset allows me to open them.
If this is what is happening, there might be some log files in the ".kobo" directory. -- I can't check this right now but I will tomorrow.
With all this, what do I suggest:
- Check the database. If it is corrupted, you need to fix that. -- done
- When you put books on the device, watch for the processing. If it doesn't happen, or seems too short, check the library list on the device to see if the books are there. If books are missing, power off and on (that's better than the reset button), connect to the PC and see what happens when you disconnect. -- I also tried power off/on and then reconnecting and often the processing will happen when I eject the second time. However, it may be that it fails to process when I reconnect/eject after doing the pinhole reset, I just don't remember at this point.
- If you get the black cover for DRM'd books, restart the device, check again and if there is still a problem, resend the books. -- I've done that and I still have a black cover but I'll try again using power off/on since I'm not sure if I did power off/on or pinhole reset before resending.
Lastly, the subject says "Library books". I assume you mean books you have borrowed. -- Correct; I've changed the title to say "Public Library books." I rely on Alf when I purchase a book so I don't have to deal with Adobe, thank heavens. Having to use Digital Editions to transfer books is a huge kludge!