hey guys add me to the list of really frustrated kobo owners
Have the exact problem as described and have done everything suggested but for some reason don't get the pop up box to deauthorize either.
all was working well before the firmware upgrade - BIG FAIL from kobo
have only purchased 2 books and the 1st one downloaded perfectly with no hitches what so ever but the second one has been locked and will not open even when it shows up on my kobo as a blank box with the title ??
I am at the point of wanting to

my kobo
what a waste of $$$ I should have stuck to buying the books in hard back
as for kobo support well that is leaving a lot to be desired