How to seamlessly rate in Photo Mechanic but also edit in Lightroom?

Question

I have been using Photo Mechanic to cull my images before I import to Lightroom because Photo Mechanic is considerably faster for this step. Where I run into an issue is when I already have the images imported to LR and I want to cull using PM. I've always set LR to Automatically write changes to XMP, so I have the XMP sidecar files already.

In PM I set "When reading IPTC/XMP: For RAW Read XMP sidecar file first" see below.

The issue is that once I make a rating change in PM, I get the following message in LR:

The metadata for this photo has been changed by another application. Should Lightroom import settings from disk or overwrite disk settings with those from the catalog?

I can click "Overwrite" each time, but it is a pain because I have to select all images that were changed to confirm the overwrite. Is there a way to default to this or maybe I'm doing something wrong?

Confirmation message in LightRoom 5:

XMP Preferences in Photo Mechanic 4.6.7:

Answer 1

It would make more sense to import using PhotoMechanic, do your cull there, then place your selects into a folder that Lightroom watches for import into Lightroom (and creation of XMP, etc., post-cull). You can have Lr move rather than copy your selects, which will spare you the extra file write (provided you're not paranoid, of course - if the rename is to risky, you can always maintain copy on import). The stars you assign in PM will be written to the RAW file rather than to a sidecar, of course, and will be recognised by Lr on import. Again, that's touching the RAW file, which you may or may not consider to be too risky. If you want to maintain all changes in XMP, never touching the RAW file, then PM isn't the tool you want, no matter how performant it is.