If Lightroom is really updating the files then all you should have to do is switch back to PM and the change should be visible. If not, you can always use the 'Rescan' command in Photo Mechanic.
-Kirk
Thanks for your help, Kirk. Even with your suggestion, I can't seem to make this work.
After changing the color label of 1 photo to "green" in Lightroom, I double-checked the metadata for the JPEG file in a separate program. The "green" label is indeed one of the XMP metadata values embedded in the JPEG file.
However, in Photo Mechanic, it doesn't seem to be updating the color label for me. I tried both the "Refresh" command and the "Rescan" command, but the color label doesn't change.
Oops...I forgot to mention that I had previously labelled the photo as "blue" in Photo Mechanic (which shows up in Lightroom), but then I went into Lightroom and changed the color label to "green". Would that make a difference?
Thanks.