RAF converted to DNG not working with Windows 10

[Joakim_R]

I've converted RAW files to DNG, both RAF files (Fujifilm) and CR2 files (Canon).
But the DNG files converted from RAF won't show as thumbnails in Windows Explorer, nor can they be viewed in the Windows Photos app. The thumbnails are just an Lr logo. The DNG files I converted from CR2 files show as thumbnails and can be viewed in the Photos app without issue.
Is there something wrong with the files I converted from RAF? Corruption of some kind? Did I make a mistake converting them to DNG? I can edit them in Lightroom just like normal.

And something else unexpected also happens with all of my newly-converted DNG files.
When I double-click them, they open in Lightroom and are ready to be entered into the catalog as a new file, creating a duplicate. I'd expect them to open on the existing catalog entry.

[TheDigitalDog]

If the DNG's open for you in an Adobe product, you're fine. The inability to see a thumbnail in Explorer may be a bug there (I've seen similar such issues on the Mac) but otherwise, nothing to worry about.

[JP Hess]

Have you downloaded and installed a codec for DNG files? I found that to be necessary to enable me to view DNG files in Windows Explorer on my computer.

[Per Berntsen]

There are three options for previews when converting to DNG – None, Medium size and Full size.

If you choose None,  the Photos app, which cannot display raw files, will not display the image.

Could that be what happened?

Since you have already imported the DNG files in Lightroom, there should be no need to "open" them.  But you can set them to open with any image viewer that knows how to display DNG previews, and you'll see the embedded jpg preview.

Right click any DNG in the File explorer, choose Open with > [application of your choice] and check Always use this app ...

Note that these previews will not include your Lightroom edits unless you select the DNG(s) in the Lightroom Library, and go to Metadata > Update DNG preview and metadata.

[Joakim_R]

Ohhh... Yeah, that might have been it. Is there any way to create previews in existing files after the fact?