I put in FB15164782 asking for documentation on how SwiftData encodes/decodes struct-valued attributes.

I wish. On a closely related topic, I put in FB15164782 asking for documentation on how SwiftData encodes/decodes struct-valued attributes, but yes, more general documentation would help. And better runtime diagnostics. Adding iCloud support to a store further limits the attribute types allowed.

Answer by @shenlong2210 worked for me, though for zsh I needed slightly different syntax: sudo rm -rfv /Library/Caches/com.apple.iconservices.store sudo find /private/var/folders/ \( -name com.apple.dock.iconcache -or -name com.apple.iconservices \) -exec rm -rfv {} \; sleep 3 sudo touch /Applications/* touch ~/Applications/* killall Dock killall Finder (I didn't use the touch commands and it seemed to work for my situation.)

I only needed to add "iTunes/Media Access", not "Full Disk Access". I'd done that for a prior IT app I'd written but forgot the access toggle. I'll suggest they update the docs. [Edit: suggested at FB16323701]

Grr. Seriously, this was not working when I posted. Even after cleans and rebuilds. But now... it works. I even made a demo app, but it works there too. So to quote Emily, "Nevermind!"