[davidfor]

Originally Posted by bernard.ryefield

It's the KoboReader.sqlite file I was discussing, as I wrote this database was not cleaned up by the factory reset.

Deleting the database file and restarting is really all that is needed. In fact, if you delete and disconnect, it will probably prompt you to do the setup. It's a while since I tried that, so it might have changed.

I described the factory reset and its effect (or lack of) in my original message.

Which actually suggests the factory reset didn't happen. How did you start it? From the Device information page of the settings, or using the buttons (as detailed by DNSB)? During the factory reset there are three black screen detailing what is happening. If you didn't see them, the factory reset didn't happen.

I'm really pressed by the time and not really able to decrypt the various operations you point there.

Well, I think you need to take the time. The logout should work. And, a factory reset should work. If they don't, then there is something else happening. And, as others have said, the most likely thing is that the internal SD card in the device is failing. Replacing the card is the most likely thing to solve the problems.

And for the record, it is usually a good idea to detail what the original problem is that you are trying to solve. If we knew what the original "serious problem" was, maybe our suggestions would be different.