"Unable to save changes..." from Acorn to Photos

Keep getting this error message when I try to edit a photo from Photos in Acorn using the Extensions selection.

“Edith with” seems OK.
If I use the Share menu, Photos share to Acorn, edit, Acorn share to Photos, then all seems OK.

That is 3 ways of editing from Photos in Acorn. Is one of these the preferred way?

“Edit with” is the preferred way. Apple introduced the extensions API before they added the “Edit with” menu, so that’s why the extension is around. But, it doesn’t work as nicely as the Edit with menu.

The Share menu can work as well, but it won’t replace the original.

Thanks for the clarification! I use Share menu to load in 3-5 photos, use elements of each for a composite, and save the composite somewhere else. So, works well for me.