Originally Posted by ElliEh
I have had my Kobo Touch since Sept.is, 2012. I have not been purchasing books from Kobo but instead have been downloading them from my public library. I had no problems until last Sunday. Suddenly, my books are disappearing from my Kobo ereader when I power off. As long as I leave it in 'sleep mode' the books are there when I resume reading. I spent 45 minutes on the phone with Kobo help yesterday and several emails today. They have escalated it to Tier 2 they tell me. I have also read that Kobo Arc owners are experiencing the same problem.
That sounds like the database on your device is corrupted. Sideloading books puts them onto the device, then the device processes them and adds them to the database. If this gets corrupted, the details don't get saved properly, but the working copy in memory has the book. When the device is powered off, the database is reopened, but the new books will not be in the database.
The fix is to log out of your Kobo account on the device. The device will then restart and create an empty database. The sideload the books again and everything should be OK. If that doesn't work, you may need to do a factory reset and start from scratch.