Per,
Thanks for the pictures you sent. I am (almost 110%) sure that your problem is created by Capture NX and has nothing to do with Photomechanic or writing IPTC or XMP data to the NEF file.
Here are your Capture NX edit steps in the version you can't save:
1. Base adjustments
2. Crop
3. Levels/Curves
4. Fit photo
5. Color Profile
6. USM (Unsharp Mask)
I started to play around and found that the problem was somehow connected to the Color Profile edit step. First I thought it's because you convert to Nikon sRGB 4.0.0.3000, which I don't have in my version of NX, I only have Nikon sRGB 4.0.0.3001. But that's not it.
I found that if you either uncheck (or delete) step 5 (color profile) or step 6 (USM) you can save the version.
So I tried what happens if you change (reverse) the order of edit steps 5 and 6 as following:
1. Base adjustments
2. Crop
3. Levels/Curves
4. Fit photo
5. USM (Unsharp Mask)
6. Color ProfileAnd surprise, now it works and you can save the version.
I tried this on your original file, your problem file, several of my NEF files (both out of camera and with PM captions applied) and even with some JPG fiels, and it is true in all cased that if you have
the 'Color Profile' step followed by a 'USM' step,
Capture NX can not save the file anymore. I tried several other combinations of 'Color Profile' steps followed by other edits steps (not all possibilities of course) and could save the file every time without problem, so it seems that only if you apply 'USM'
after 'Color Profile' it causes problems.
Check the other files you can't safe and see whether you have this particular order of edits. If yes, just reverse them (UMS
before Color Profile) and it should work.
You may want also to contact Jason P. Odell (author of The Photographer's Guide to Capture NX,
http://www.luminescentphoto.com/). He may know about this problem and give you additional information.
Let me know what you find and whether you got my sample pictures (3 total).
Regards,
Archer