Lens Profile changes in ACR 6.2 update

Question

Before the update, I had perfectly aligned masks for hundreds of images using the Nikon 18-200mm lens.  However, when I now open their Smart Objects, make and change and close, a new distortion correction is being applied, ie. the masks are not longer aligned.  This is a major headache and it's not clear how I might go back to the original lens profile.  Even if it is worse, I am already invested in it with the masks.  Pushing out this change without due notice or way to ensure backward compatibility is a major shortfall.  I would be interested to hear how Adobe recommends I proceed?  Revert to ACR 6.1 and miss out on all future updates?  I highly recommend building legacy profiles into future updates.

Answer 1

What ACR adjustments do you need to do to the image that can only be done in RAW format and cannot be done when ACR is editing a TIF after your initial ACR-conversion?  It seems as though you may need to modify your workflow to convert to TIF, and then re-edit that TIF with ACR and use that as the smart object on which to apply your masks.  TIFs only have relative WB adjustments, not absolute like RAW files, but if the WB is close you probably don't have to tweak things too much, although you'd want to be careful to create your initial set of TIFs with the same initial WB so you could tweak groups of images similarly with the same relative adjustments.
For Adobe to accommodate what you're wanting they'd need to have the ACR version number where a profile came from as part of its name so ACR can match the specific profile used with old images.  I think Adobe messed up when they didn't do this, initially, but perhaps they feel it is still a beta period and don't want too many versions of each profile cluttering things until things have settled down.
You asked, earlier, how to get the old profiles back. 
On my Windows Vista/Win7 computers the Adobe-supplied lens profiles for Nikon are duplicated in two different places:
C:\ProgramData\Adobe\CameraRaw\LensProfiles\1.0\Nikon
C:\Users\All Users\Adobe\CameraRaw\LensProfiles\1.0\Nikon
I think additional users-supplied profiles would go to the following place, although I'm not sure because I don't have any user-created lens profiles:
C:\Users\-your-user-name-\AppData\Roaming\Adobe\CameraRaw\LensProfiles\1.0\Nikon
The way to get your old profiles back would be:
Find the current Adobe-supplied profiles on your computer and remove them.
Download and install the ACR 6.1 update.
Find the profiles installed with that in the same places you removed the other ones from and save all these 6.1 profiles somewhere else.
Download and install the ACR 6.2 update.
It may be sufficient to copy the old 6.1 version of the profiles for the lenses you use into your user-profile-specific location and those would override whatever Adobe-supplied profiles there are, but I doubt it. 
And if not, then what you'd want to do is edit the XML in the LCP files for ACR 6.1 for your lenses that you have already put into your user-profile-specific location and change the name to have the ACR version in it, so when you run LR or ACR, you know which ones are your old profiles and which are the current ones that Adobe has supplied.
The remaining task is to re-assign this relabeled ACR-6.1-specific profile to your underlying images that have smart-objects in them to be able to use your masks with the old correction in place.
Going forward it might be wise to also copy and relabel each profile for your lenses that have been updated...you may have to test things yourself to see if there are any differences.