For as long as I've shopped there, Kobo has always had an issue with not letting customers download copies of all of the ebooks they buy. I've never understood why and they've never supplied a consistent answer, but some of the ebooks bought at Kobo can only be read in Kobo hardware and apps.
Edit: This post is being updated on 29 January 2019. The instructions worked on that day.
Historically this has been a minor issue, but there are a growing number of reports lately, both on Dear Author and on MobileRead Forums, that suggest that the problem may be getting worse (there's also one report that claims this is a new problem, but it is bogus).
It's not clear whether the increase in reports are the result of more titles being affected rather than more customers encountering the issue, but since there are a growing number of complaints I would like to offer a solution.
There is a calibre plugin which can grab all of your Kobo ebooks, convert them from Kobo's own funky Kepub format, strip the DRM, and add them to your calibre library.
It's called oboK, and it works with the Kobo for PC app. You'll need to download the ebooks with Kobo's app first, and then run calibre. With a minimum number of clicks, the oboK plugin should be able to rescue most of your DRMed ebooks. Some formats aren't supported by the Kobo4PC app (graphic novels, for example) and can't be downloaded.
You can download the plugin here:
Or the older version here:
The Usual Disclaimer
oboK, and the instructions provided to help install it, is intended strictly for personal use to enable a reader to rescue their purchases from the clutches of Kobo and the publishers. Please don't pirate.
Like any calibre plugin, you can install it by right clicking on the preferences button, scrolling to the bottom of that menu, and then selecting the plugins option. When that menu pops up, select the option to load a plugin from a file.
Installation should be easy, and once it's complete you should have a new button on the menu bar. Click it and the oboK plugin will spring into action. A new menu will appear and prompt you to select which of you Kobo ebooks you would like to rescue.
To be completely honest, I have not been able to get the plugin to work. But I am told other people have, and so I am sharing it with you today.
Update: I've solved my problem by deleting and reinstalling the Kobo app. Now Obok is able to rescue my Kobo purchases.
If you have a problem getting oboK to work, and then solve that problem, please leave a comment. I would like to be able to use it myself. Thanks!