P: unknown error while writing metadata to this photo

Try resetting the tablet Preference file using the Wacom 'Tablet Preference File Utility' 'Remove' function. Make a 'Backup' first using the utility so you can  'Restore' it if the issues persist.

Yes, I have this problem with my Wacom Intuous Large tablet. The "Rotate" function will not work. I called Wacom, and they were stumped. The tech guy told me it was Adobe's fault. I explained that Wacom was supposed to work with Photoshop, but he didn't agree and concluded the troubleshooting session. I suspect Wacom will discover they have a small flaw in their software, fix it and update the driver. Until then we might be stuck.

In the Lightroom CC preferences, you can check an option to store the originals on your hard disk and in a different location. Doesn't the latter create a normal folder structure?

Yep.

Its just that I have a habit of adding the root of the Lightroom (Classic) import directory to the Apple Photos, so they seamlessly sync when I import pictures into Lightroom. 

I think it would be nice to if the new Lightroom, either maintains the same directory structure as Classic or use one of the Apple supported extensions, if any. 

I see what you mean now.  As a workaround you could just browse to the photos in finder and then drag and drop them into photos.  You have to drop them on the side bar from my experience.  

Thanks, Rick. 

You are right - we can navigate through the files in 'Finder'. Perhaps, I wasn't clear in my earlier comment. I was referring to "import" function in Mac Photos App. It seem to not recognize the new Lightroom library (structure). 

You can get to the files.  They are just stored in a package, which is really just a fancy folder.  Just right click on your library file and click show package contents.  There is a folder that has a really long name that seems to be totally random characters.  Just open that up and your originals are in there organized by date.

the two listed programs were the only ones used after the photo was scanned into the computer. Once I switched to lightroom the only other programs now used is the latest version of photoshop Elements. - as noted before if I used the latest elements to write a keyword to the photo in question, then go back to lightroom and try writing a keyword from there it works. Apparently when the latest elements updates the photo it overwrites whatever anomoly keeps lightroom from succeeding its actions.

See related problem:

http://feedback.photoshop.com/photosh...