Problem with the file - is not with XnView MP.
Below is my message to Richard (Butler), DPReview's Technical Editor:
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Hi Richard,
Sorry for disturbing you.
Just a quick note about the raw file of the photo from
https://www.dpreview.com/sample-galleri ... 8968412635
It seems that the file is corrupted.
Facts:
All/most the raw files in that gallery are @45-50 MB - this one is @25 MB.
Someone else had the same problem:
viewtopic.php?f=82&t=38428
(from where I start to investigate)
I downloaded more file from that category - eg.
https://www.dpreview.com/sample-galleri ... 0090248310
...and while all files have the JPEG preview intact, the one above has the actual full size Raw data damaged.
In order to test it, you can download XnView MP from
viewtopic.php?f=82&t=37945
And open it on the folder in which you have the RAF files. You will see that all the thumbs are generated correctly.
If you will go in Full Screen mode (eg. by pressing F11) or in Edit mode (by double-clicking on the file), then:
1. If the program is set to read the actual Raw data, the after-mentioned file is shown as a black rectangle
2. If the program is set to read just the embedded JPEG then the program shows it correctly
This phenomenon happens only with the file in cause and not with other files from the same camera.
Hints:
1. You can change the reading mode between Full / Half Raw and Embedded JPEG in Tools | Settings | Formats | Read | Camera Raw (it is the first Drop-Down box at top, called "Use").
2. You can use the 2ndary monitor for Full Screen mode = check in Tools | Settings | Fullscreen the "Dual Monitor" checkbox.
3. The raw engine of XnView MP is based on dcraw, a widespread standard in this industry.
4. XnView MP, despite of its version number (no, I don't agree with the version number

) is a mature program, developed continuously and used by many users (disclaimer: I don't have any affiliation with the developer) for managing Raw files because (AFAIS) it has (one of) the fastest thumbnail generation, preview and Batch Convert engines available. Besides that, even if it isn't a Raw editor like eg. Lightroom it is much more scalable than it, hence the program was tested with many, many raw files till now.
Just my 0.02 cents & hoping this helps,
John Thomas