Thank you for the sample files. The files in the woIPTC folder do not have either the IPTC or XMP metadata sections, so it looks like Photo Mechanic's Delete Metadata utility is working correctly. The Exif section has the Image description ( caption field ), the Artist ( photographer field ), the Copyright ( copyright field ) and Software ( Adobe LR 6.10.1 Mac ), written by Adobe.
If you need this metadata removed, then you can use Photo Mechanic's Delete Metadata and check the Exif box. This will remove caption field, copyright and photographer info plus all the camera info including the original capture date. If you just want to clear the Caption, Photographer and Copyright fields and maintain the rest of the Exif metadata, then you can do 2 things. Use Photo Mechanic's IPTC Stationary Pad to batch erase these fields. Just check the Apply box for the Caption, Photographer and Copyright fields and leave the fields empty. The Exif section will still have the Image description, Copyright and Artist metadata by Photo Mechanic and Photoshop will no longer display the metadata due to an IPTC record with empty caption, photographer and copyright fields. If you want to completely remove the Exif Image description, Artist and Copyright metadata and preserve the remaining Exif info, then you will need to open the file in Photoshop, open the File Info from the File menu and clear these fields. Now when the file is saved, the Exif section will not have any of this unwanted metadata.
--Bob