Whenever I try to add data to the IPTC of a TIFF file I get this message
There were errors during the apply to selected operation. What is the problem I have
I don't know. You haven't provided enough information.
What version of Photo Mechanic are you running?
What OS are you running?
What kind of TIFF is it?
What application or device produced the TIFF file?
If you try and add IPTC to the file directly with the IPTC Info dialog does it fail as well?
-Kirk