Upgraded to Adobe Digital Editions 2.0 and having trouble opening ebooks on ereader

[Guest]

I upgraded to Adobe Digital Editions 2.0 from 1.7 which I use to borrow ebooks from the library.   I transfer the ebooks from my computer to my Kobo ereader.  Everthing was working just fine with version 1.7.  Since upgrading to version 2.0 I can no longer open ebooks that I have transfered to my Kobo ereader.

I checked and Adobe Digital Edition verion 2.0 and it indicates that both my computer and Kobo reader are authorized.

[sjpt]

ADE sometimes gets registrations confused and half registered.

Probably worth deregistering and re-registering.

To de-register the computer, ctrl-shift-D to ADE (cmd-shift-D on Mac), restart ADE, and then reregister.

That may well be enough, but if needed:

to de-register the device, ctrl-shift-E to ADE (cmd-shift-E on Mac) with the device plugged in, restart ADE, and then reregister.

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There are also bugs in ADE2.0 that mean using it with some eReaders goes OK with most books, but not with Overdrive library books.

My Sony PRS-350 is an example.  The only solution I found was to revert to ADE 1.7.2.

(Quite a few other bugs in ADE2.0 as well).