Once again they have found another way to break iTunes, no way to download podcasts and settings refuses to subscribe to individual podcasts which have mysteriously reset themselves (randomly) to unsubscribed, so sick of a new problem with every update.
OS X Mavericks (10.9.3)
i have this problem too. But at least all the old Podcasts are still in my iTunes music library. The podcasts I had in Mail seem to have disappeared completely. A valuable collection I had of "must-listen-again" podcasts disappeared and I don't know what I've missed.
I hope someone will reply to your message and let us know what options we have.
iTunes 12.2.145 Podcasts
