Clara BW Spurious entries in books list

[bluepeter]

I've just acquired a new Clara BW. If I open My Books, I find a list of authors, none of whose books I own, let alone have loaded onto the device. The attached photo shows a small part of the list under the series tab. If I tap on any of them, I get a screen saying "You have no books yet". If I tap and hold an entry, nothing happens.

How can I get rid of these spurious entries?

If I need to edit a database or something, I'll need detailed instructions, please. My relevant knowledge is negligible.

EDIT: a factory reset doesn't resolve the problem - the fake entries are still there.

[bluepeter]

OK, problem now solved. Procedure as follows:

1. factory reset;
2. activate with my Kobo account;
3. factory reset;
4. now set SideloadedMode = True

(I originally set it to sideload mode straight out of the box.)

It's mildly irritating that I had to register the device to an account just to get rid of the cruft, but not the end of the world.