This absolutely works!!! I saved a copy of the protocol file to my desktop ... opened the same folders on my current Mac and replaced the asset propcol ... restarted AFD and. ...Boom! Glory Days! ... Huge Thanks!
My backups were made using Time Machine, and I've been able to successfully restore everything from there! Here's where I found everything that had gone missing:
Users > "username" > Library > Containers > com.seriflabs.affinitypublisher > Data > Library > Application Support > User
Inside that folder, the assets.propcol file is what I restored for my missing assets. I also had to restore my macros.propcol, doc_spread_presets.propcol and object styles.propcol files as all of my previously saved macros, document presets, and styles were missing.
In case it makes a difference, my affinity apps were all purchased through the Mac App Store. Hope this helps!
eyanobi got a reaction from Dan C in Restore presets after updating to macOS Catalina