MD Item Description not writeable?

[dixonge]

Earlier today I ran an exiftool command that successfully copied the title field to the description field for several images in a directory. Unfortunately there are a *lot* of remaining images where this command was not successful. If I try 'exiftool -Description<Title' I get 1 updated file and 427 not updated, all of whom show "No writable tags set" (it is possible that this is for files with no Title data) - If I try 'exiftool -MDItemDescription<MDItemTitle' no files change, all show the same error messages, with quite a few adding an extra line to tell me that "mditemdescription is not writable"

Yet I can easily manually copy the Title field to the Description field using ApolloOne, for example, or XnViewMP.

So what am I doing wrong?

[StarGeek]

You seem to not realize that these are all completely different tags.  MDItemDescription and MDItemTitle are Mac OS specific tags that are not writable by exiftool (see MacOS tags).  They are not embedded metata and are part of the underlying file system.  If you moved the file to another OS, such as Windows or Linux, they would be lost.

Title and Description are embedded in the file and can both be written by exiftool.

If you try to copy Title to Description ('-Description<Title') and exiftool says that there are no writable tags, then that means that the Title tag does not exist in that file.  The doesn't preclude the existance of a MDItemTitle.  If that is the title tag you are looking to copy, that would be a separate operation ('-Description<MDItemTitle').

I would suggest you use the command in FAQ #3 with the addition of the -API RequestAll=2 option to see all the tags for the file and their locations.  You can then look for specific tags on the Tag Names pages to see what is and isn't writable.