The Problem
This is a bizarre problem with obscure origins. When opening an image in Photoshop from Lightroom using the ‘Edit in’ command does not always apply the lens profile. Some lens profiles work and others do not.
Investigation
The lens profiles that do not work are newer profiles available after upgrading Lightroom, and possibly also Photoshop. Older profiles work satisfactorily. However, using the ‘Export’ function does create image files (e.g. PSDs and JPEGs) with the newer lens profiles correctly applied.
Opening an image in Photoshop from Lightroom as a ‘Smart Object’ and then opening in Adobe Camera Raw the ACR Optics panel will display the message ‘Unable to load lens profile’.
Clarification
Lightroom accesses its own folder of lens profiles. ACR has a separate, but nominally identical, folder of lens profiles. Copies of lens profiles folders from previous installations can remain on the hard disk, but which will not contain the newer lens profiles.
When an image is opened in Photoshop from Lightroom it uses Camera Raw to apply the edits made in Lightroom to create an editable file, including applying the lens profile.
Analysis & Diagnosis
It appears that Camera Raw was unable to access the newer lens profiles. If ACR cannot access the same lens profile as used in Lightroom then the errors described above will occur.
Speculation
In my case I believe that I inadvertently opened an older copy of Lightroom which may have caused ACR to become confused about which folder/profiles to access. It is not altogether clear where this error occurred as deleting preference files for Lightroom, Photoshop, and ACR made no difference.
Solution
An hour and ten minutes on the phone to a very patient Adobe Technical Support technician produced a solution. This involved manually deleting the ‘CameraRaw’ folders from the Mac’s Libraries (root and user) and deleting the Camera Raw plugin. ACR was then reinstalled using a link to a download provided by the technician.
Happiness!
