When my photos were moved from iPhoto to Photos in the last system upgrade, they lost all their titles. How can I restore them?

Question

In the latest Yosemite upgrade, my photos were migrated from iPhotos to Photos and lost all their titles. How can I restore them?

Answer 1

There is an Applescript, File Name to Title,  provided by user léonie that will put the file name of any selected photos into the Title field for that photo.  If there already is a title in that field under the thumbnail it will not replace it with the file name. 
tell application "Photos"
  activate
  set imageSel to (get selection) -- get a list of selected images
  set counter to 1
  set currentfilename to ""
  if imageSel is {} then
  error "Please select an image."
  else
  repeat with im in imageSel
  set title to the name of im
  if not (exists (title)) then
  set currentfilename to the filename of im as text -- retrieve the filename of image "Im"
  set newname to currentfilename & "." & counter
  set counter to counter + 1 -- increment the counter
  set the name of im to newname -- write the newname to the title field
  end if
  end repeat
  end if
  return currentfilename -- return the filename of the last image
end tell
Copy the script above, open Applescript Editor and past it into the open window.  Compile and save as an Applescript application.  Put the app in the Applications folder and drag into the Dock. Now you can select images in Photos and launch the app from the Dock and it will do it's thing.  It is a bit slow so can take some time for a large number of images depending on the speed of your Mac.
Just to be on the safe side create an album with a few titled and untitled photos and run it on them.