Metadata xmp dc description

[hannes_hab]

I wonder why if I add a description in another software (ASP) this is not shown in Imatch (is shown in XNview MP for example). Its saved in a .xmp sidecar file.
Whats is the reason - preferences?

[Mario]

Most likely your other software has only written some XMP data but not updated the original EXIF:description or legacy IPTC description in your file.
I have written about this so many, many, many times in so many posts. I won't explain this again. Please use the search function in the community.

Run the The Metadata Analyst for the file to see the problems in the metadata.
Then fix it. If you want to post the results of the MDA, use the GREEN BUTTON at the top.

I would guess the other software you have used did only update some XMP fields but not update the native description in the image file. Thus overriding the XMP description.
There are multiple metadata tags containing the description, in EXIF, IPTC, IDF and XMP. If your other software updated only one - too bad.
Do not use software in your workflow to manipulate metadata unless you are really sure that the software does it correctly.

Recommended Reading:

Metadata for Beginners
Metadata Problems and Pitfalls

[hannes_hab]

Metadata Analyst:
[ExifIFD]:UserComment and [XMP-dc]:Description (sidecar) mismatch.

How to fix it?

[Mario]

Enter the description in IMatch and write back.
This will update the XMP and all linked descriptions to the same value.

[hannes_hab]

it seems that its only a problem with nikon .nrw not with nikon .nef files

[Mario]

This depends on the metadata contained in the RAW file.
Not on the specific RAW variant your camera uses.
Some NEF files contain legacy IPTC data. Some NRW files (and some NEF files) may contain a rudimentary XMP record, usually only with a hard-coded rating=none.
All this may cause issues.

You need to run the MDA on the file to learn more.