After I run the below line in MS-DOS with different jpg files. Some iptc are updated and some return the error "Error: Bad Photoshop IRB resource".
exiftool -iptc:ObjectName="Glen Etive" glen-etive.jpg
The IPTC is stored in the Photoshop IRB resource data in JPEG files. Somehow the IRB resources in these files are corrupted, so ExifTool can't write the IPTC. Without seeing a file I can't be more specific about the exact problem.
- Phil