After the upgrade to Mac Os Catalina all books and PDF's disappeared.
I tried re-installing Adobe Digital Edition.
I tried de-authorization and then again authorization.
Synchronization is activated.
I signed out and in again.
I started the Mac again.
I asked the helpdesk and we searched for over an hour for a soultion.
Then I was advised me to tell about the problem here.
I am grateful for help.
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