Comments Missing from Files on Mac mini

Thanks for pointing out that was too lazy in my initial test.

You are right: Finder no longer displays comments from exFAT (MBR) volume after it is re-mounted. But the metadata tags are still there and can be exported with this command:

exiftool -q -s3 -if '$MDItemFinderComment' -p '$filename: $MDItemFinderComment' . 2> /dev/null > comments.txt

How can I export file comments in Finder … - Apple Community

Or update the files so Finder again displays their comments:

exiftool -m -P -ext txt -ext jpg -overwrite_original_in_place -tagsFromFile @ -MDItemFinderComment .

Notice that exiftool by default does not handle .txt files so it must be defined with '-ext txt' option. On the other hand, .jpg files do not need that if only they are updated. I copied the test files to an APFS volume before that command. For some reason on a FAT volume it worked only for a .jpg file and a .txt file did not reveal Finder comment until it was copied to APFS and that command was executed.

APFS and MacOS Extended do not lose Finder comments after re-mounting.

> mdls via Terminal on one of the files on my ExFat formatted flash drive. I see that FinderComment is indeed there, but it shows as ""

Yes, it seems that a exFAT/FAT volume does not generate the needed MDItemFinderComment from the XAttrMDItemFinderComment like an APFS or MacOS Extended volume do.

The only option seems to use APFS or MacOS Extended format. If the files have been on non-Mac volumes then the comments still might well be there but are not displayed until the files are moved to a Mac-formatted volume and a command like below is used to reveal them.

exiftool -m -P -ext txt -ext jpg -overwrite_original_in_place -tagsFromFile @ -MDItemFinderComment .

What kind of documents do you share with other users? Are they Mac-only or also Windows and Linux users?

Image files support IPTC/XMP metadata that is cross-platform and robust. AFAIR .pdf supports internal metadata that might be useful for this purpose.

Finder comments are stored in XAttr metadata:

exiftool -a -G1 -s -api RequestAll=2 a.txt 
[MacOS]         MDItemFinderComment             : Finder comment
[MacOS]         XAttrMDItemFinderComment        : Finder comment

I tested this and those tags survived a detour to exFAT and FAT (MBR). But that test was done on the Mac so they might not survive a detour to Windows.

AFAIK it is possible to insert metadata to formats like .pdf that should be robust. Or a sidecar file that has metadata.

> upon shutdown/restart on my Mac or dismount/mount on my flash drive (OS Extended) the visible Comments are gone

In my tests MacOS Extended and APFS volumes preserve visible Finder comments after unmount and reboot. Maybe your were too fast and there was no enough time for the system to generate the needed MDItemFinderComment from the XAttrMDItemFinderComment? I've noticed that it might sometimes take a while (maybe 30 seconds or more?) for that to happen.

> flash drive

What format is it (APFS, MacOS Extended, some non-Mac format?)?

I have never put any important info to Finder comments. In ancient System 4-9 they were deleted unless some 3rd party utility was used when "rebuilding the desktop info".

Matti,

Although the Finder comment metadata travels with the file to the mounted exFAT drive, and a Get Info prior to unmounting the drive does show the comment, a subsequent eject and remount of the drive loses the Get Info comment text.

The comment metadata tag remains on the file and so does the actual comment — it's just not visable in the Finder via Get Info or in a List view Comments field. The following proves that the comment remains on the file:

Copying the same file back to an APFS formatted filesystem location does not restore the comment in a Get Info panel.

I copied the test files to an APFS volume before the command below because on a FAT volume it didn't seem to always work. It seems a FAT volume does not generate the needed MDItemFinderComment from the XAttrMDItemFinderComment like an APFS volume does.

exiftool -m -P -ext txt -ext jpg -overwrite_original_in_place -tagsFromFile @ -MDItemFinderComment .

> .pdf option?

I did a quick test with .pdf which seems to behave essentially the same as image (.jpg etc) and movie (.mp4, .m4v, .mov) files.

For example, add the following tags to a .pdf with exiftool:

exiftool -overwrite_original -api LargeFileSupport=1 -Author='Charles Dickens' -Title='A Tale of Two Cities' -Subject='A historical novel set during the French Revolution' document.pdf

It is stored as:

exiftool -a -G1 -s -api LargeFileSupport=1 document.pdf         
[PDF]           Author                          : Charles Dickens
[PDF]           Title                           : A Tale of Two Cities
[PDF]           Subject                         : A historical novel set during the French Revolution
[XMP-pdf]       Author                          : Charles Dickens
[XMP-dc]        Title                           : A Tale of Two Cities
[XMP-dc]        Subject                         : A historical novel set during the French Revolution

"The above command used on a PDF will write to both the PDF tags and the XMP tags, which should cover all the bases."

Finder > Get Info and Preview.app > Inspector display that as:

exiftool does not yet support writing to formats like .txt, .docx, .xlsx, .pptx but you might ask its developer if that is possible.

GraphicConverter 12 has an easy GUI to add Title and Caption/Description to .pdf (and to images and movies) that Finder > Get Info and Preview.app > Inspector display as follows. You might ask its developer to if it possible to add more options.

[XMP-dc]        Title                           : GraphicConverter Title
[PDF]           Title                           : GraphicConverter Title
[PDF]           Subject                         : GraphicConverter Caption/Description

https://exiftool.org/forum/index.php?topic=11650.msg62568#msg62568

https://exiftool.org/TagNames/PDF.html