[Vintage Season]

Given the amount of frustration this subject has caused, I revisited it is afternoon… and somewhat to my surprise, actually got it working (at least for my daughter's Kobo Aura One; YMMV with a Forma, since I've never seen one of those to test).

We stumbled upon this approach because my daughter had been using the OverDrive app for years, but had originally used a card login for each library, and only created an OverDrive account two weeks ago. Below are the semi-simplified steps we took, some of which are likely unnecessary, although they were retained simply because the success was repeatable when using them. I'll apologize in advance if any of this is too redundant given all the discourse above, and for the fact that these steps entirely ignore the existence of a Libby app, since neither my daughter nor I use it.

1) Nuke your OverDrive account, from within the Overdrive app. This entails signing out of each library you might already have added, then deleting each library from the stored list, then clicking on the "Manage account" button from within the "Account" menu item and checking the "Libraries" tab to ensure no libraries remain.

2) Remove the Overdrive app from your device.

(If you had the OverDrive app on multiple devices, you might wish to repeat the nuke/delete for each one. We did, to be safe.)

2) Sign out of OverDrive on your Kobo.

3) Add the OverDrive app back to one of your devices, and log in with your OverDrive account.

4) After you have logged in with your OverDrive account, add your library cards to the OverDrive app.

5) Select one of your libraries, and sign in to your Kobo with your OverDrive account. Even when prompted, do not yet add a card number! "Maybe later" means you'll do it later.

6) From within the OverDrive app on your selected device, check out an ebook using the same library you selected on your Kobo.

7) Sync your Kobo. Nothing should happen… yet.

8) Go back into your OverDrive settings on the Kobo, and add the card number and PIN for the appropriate library.

9) Sync your Kobo again. The book you checked out will be added to your Kobo… which is the expected behavior, since it's from the library you selected for the Overdrive login.

10) Repeat steps 2–9 for each additional library from you wish to read.

11) Pick whichever library you'd wish to browse from the device, as your final (re-)login to OverDrive on the Kobo.

12) Check out additional books from each library via the OverDrive app, to ensure each is still working…

… which is probably an awful lot of work, but since my daughter can now synchronize books across five different libraries on her Kobo, it was worth it for us.