The “Magick: caught exception 0xC0000005 “Access violation”…” text is from the darktable log file …
The HDR DNG file was created in darktable “Actions on selection / Create HDR”, then two edits were created (using “Duplicate” function). One of the edits exports to jpg fine, the other one crashes dt.
Export to tiff is working fine for both edits (i. e. xmp files)
From the manual
https://darktable-org.github.io/dtdocs/en/overview/sidecar-files/sidecar/
For a given source image, multiple editing versions, called duplicates, can co-exist, sharing the same input image data but each having their own metadata, tags and processing steps. Each duplicate of a given image (named
<basename>.<extension) is represented by a separate XMP sidecar file (with a filename constructed in the form<basename>_<number>.<extension>.xmp, where<number>represents the version number of that edit). Information for the initial edit – the “duplicate” with version number zero – is stored in the sidecar file named<basename>.<extension>.xmp. The version number of each duplicate is displayed in the image information module in each of darktable’s views.
Forgot to mention: you can assign names to versions in the darkroom.
Then, in the XMP file, you’ll see those names, for example:
<rdf:Description rdf:about=""
...
darktable:version_name="duplicate #2"
...
>
Thanks for the info, but I still have two identical names in lighttable, and two distinct (xmp) names on the disk. Therefore I can’t unanimously identify which xmp belongs to which image in lighttable, or …?
Assign them a name in the duplicate manager.
Also, in the duplicate manager, you can see the number (above: 0, 1, 2 – 0 is whatever.ext.xmp, 1 is whatever_01.ext.xmp and so on).
Yes, I know that, but how do these labels from duplicate manager reflect in the xmp files?
And what if the duplicates are not labeled in the duplicate manage (happens to me quite often, that I do not label them)?
This could be functioning, thanks for the information. But this means that I have to open each file in Darkroom to see the labels. There is no way in Lighttable to tell the two duplicates apart (except for the editing differences visible in the thumbnails).
Maybe a suggestion: name the duplicates in the lighttable the same as the pertaining xmp files, and the association is perfect …
There are no “real duplicates” of the raw files, only two different edits (resulting in different xmp files) for one raw file.
Unless I misunderstand your question, I’ve already answered it. You can open the XMP files in any text viewer, and then:
Yes, that is what I’m talking about: we have two xmp files associated each to one “image” in the lighttable (the image data coming from the common raw file, and the editing data coming from a xmp file).
But the “image” names in lighttable are identical, so there is no way to unanimously associate an image in lighttable to one of the two xmp files.
The only way, as the fellow commenters have indicated, is to go into Darkroom and check the duplicate numbers in the Duplicat manager module …
No, please read the manual !
Yes, but there is no way to identify the duplicate number of the “image” in lighttable. I have to check them up in Darkroom …
I think they are suggesting to look here…
Yes, correct, thank you for the info!
I must have overlooked that 
The problem of XMP file identification/association is clear/solved.
Thank you all for your help!
Remains the main question about darktable crashing while exporting (dt created) HDR-DNG image to jpg file …
There is a way with overlays… add permanent or hover …set to extendend and modify the variables added in the preferences for Lighttable view to add $(version.name)
I just stuck it at the end but you can format the sequence as you desire…
Here I just called them one and two… you can also just use version number that variable is $(VERSION)
EDIT if you wish to extend or further configure you can read about it here…
https://darktable-org.github.io/dtdocs/en/special-topics/variables/
Where is the log from a crash?
I tried the DNG exported both versions at full and the downscaling shown by the OP and not issue… Pretty slow on this old Windows 10 PC that I have at work maybe 1 min or so to export each but no crashing…
I have an old NVIDIA 4GB GPU 700 series …
So I can’t reproduce the crash at this point… on this hardware/OS combo
I mentioned it before (Magick: caught exception 0xC0000005 “Access violation”…), but for the record, here is the log file from two subsequent crashes:
darktable-log.txt (114 Bytes)
Thanks for the info! Did you export to tiff, or to jpg?
Now, that you mentioned it, I tried exporting it also on my old PC (windows 10, Nvidia GTX970, 4GB GPU), with the same result, except that here also export to TIFF crashes.
But as I mentioned before, the settings (Performance, OpenCL, …) have no influence on this crash (at least on my machine(s).
