DNG thumbnails not showing in W10 folders

[Tafflad]

Not specifically LR, but as my DNG photo are all for LR, there may be someone here who knows how to resolve the problem.

Windows 10 and LR Lightroom version: 6.14 [ 1149743 ] 

If I go to a Windows 10 folder - all of the jpeg files with have a thumbnail  (as do png, tiff etc)
Very few DNG files will have a thumbnail (usually none)

I have installed Microsoft raw image Extension .... v3 no difference
Have followed the steps to kill thumbnail cache, delete it, and restart explorer ... all jpeg thumbnails rebuild (slowly) but not DNG.

Have also followed the tip to uncheck 'always shows icons, never thumbnails'The advice is to click on teh top button 'apply to folders'  but I can't do that as that is greyed out.  (pic attached)

[John R Ellis]

Which app or exact camera model produced the DNGs?  If LR created the DNGs, which command (Convert Photo To DNG, Enhance, Photo Merge)?

[Tafflad]

My phone creates DNG files directly  ..  my camera has to have the raw files converted and I use ADOBE DNG converter to do that.

Just did a test and showed something I had not realised before.

File saved to Desktop ..... and it has the correct thumbnail.

When I move file to a sub-folder  of My_Pictures  is arrives there without a thumbnail.

LR identifies the RAW file whether on desktop or in a my_pictures folder

Noticed another anomaly .... on my phone the selection is simply to output 'RAW' files.

They arrive on PC as filename.DNG

I just opened file with Mediainfo and it reports it as an invalid tiff ?  (see attached)

[Tafflad]

I deleted thumbnail cache, increased cache size to 4MB and rebuilt cache.

Still the same, initially all files in example folder were not thumbnails..... in aprox 30 sec jpeg thumbnails arrived and 2 of the DNG went solid colour - sometimes they then change to proper thumbnails ..... as you can see other DNG still without thumbnail.

[Tafflad]

As another test took a pic with camera ... it saves in RW2 format (Lumix)
Media info advises little:
General
Complete name : C:\Users\Rick\Desktop\P1001487.RW2
File size : 23.1 MiB

I use the Adobe RAW file converter and it turns it into a DNG file.
Media Info advises:

General
Complete name : C:\Users\Rick\Desktop\0102P1001487.dng
Format : TIFF
File size : 18.7 MiB
Writing application : Panasonic Adobe DNG Converter 11.3 (Windows)
Writing library : DC-GX9
FileExtension_Invalid : tiff tif

Image
Format : Raw
Format settings : Little
Width : 256 pixels
Height : 192 pixels
Color space : RGB
Bit depth : 8 bits
Compression mode : Lossless

Encoded date : 2024:02:01 14:14:23

So here is the anomaly .... an original DNG file is tagged as FileExtension_Invalid: tiff tif
A converted RW2 file to DNG is also tagged as FileExtension_Invalid: tiff tif

The converted file on desktop had no thumbnail, but when I double clicked to view, it then created a Thumbnail.
However when I move it to a sub folder of 'My_Pictures' it once again has no Thumbnail.

THis is teh file in case you want to view it

https://www.dropbox.com/s/jpgp44kocbwb4ck/0102P1001487.dng?dl=0

[John R Ellis]

So here's my understanding so far:

1. You have two sets of DNGs, one set produced by the camera app on your Samsung Galaxy S21 phone and one produced by applying Adobe DNG Converter 11.2 (five years old) to .rw2 raws coming from from a Panasonic Lumix DC-GX9.

2. With both sets of DNGs, Windows 10 File Explorer has problems displaying their thumbnails.

3. With the Lumix DNGs, File Explorer initially displays the thumbnails when you save the DNG to Desktop, but when you move it to another folder, the thumbnails don't display. 

4. The Media Info utility thinks that the Samsung DNGs are in invalid TIFF format.  I can't find the authoritative documentation for that utility, but all the download sites indicate it's focused on video and audio files. The DNG file format is based on TIFF, so it's not surprising that a utility not specifically focused on raw formats gets confused by them. Ignore Media Info.

5. With the sample Lumix DNG you provided, I don't observe the symptoms you do with Windows 11 File Explorer -- it always displays the DNG's thumbnail, regardless of which folder I move or copy it to.

6. You didn't provide a sample problem Samsung DNG.  Please upload one to Dropbox.

7. I observe that DNGs produced by LR's Merge and Enhance commands don't display their thumbnails in Windows 11 File Explorer.  While it's possible that those DNGs don't strictly obey the DNG standard, given that Adobe invented the DNG format and that Mac Finder and other apps can display the thumbnails, I think it's much more likely that Windows 11 File Explorer is buggy with respect to them.

8. Your Adobe DNG converter is version 11.2, five years old.  The latest version is 16.1:

https://helpx.adobe.com/camera-raw/digital-negative.html#downloads

I suggest installing that version. It's capable of generating all the different versions of DNG, so if the latest DNG versions are choking Windows 10 (also five years old), you can experiment generating older versions of DNG with the converter.

9. Windows, like Mac OS, isn't very fussy about fully supporting all the common file formats out there. I think it's likely that if you continue to experience issues with DNGs after updating to Adobe DNG Converter 16.1, you're tripping over Windows 10 File Explorer bugs that may not be present in Windows 11. 

[Rikk Flohr: Photography]

regarding #7:
7. I observe that DNGs produced by LR's Merge and Enhance commands don't display their thumbnails in Windows 11 File Explorer.  While it's possible that those DNGs don't strictly obey the DNG standard, given that Adobe invented the DNG format and that Mac Finder and other apps can display the thumbnails, I think it's much more likely that Windows 11 File Explorer is buggy with respect to them.

The likely cause here is that the Merge and Enhance use JXL Compression, and the OS manufacturers haven't released support yet. 

[John R Ellis]

"The likely cause here is that the Merge and Enhance use JXL Compression, and the OS manufacturers haven't released support yet."

I forgot about that. Interestingly, Mac OS 14.2.1 Finder shows thumbnails for Merge and Enhance DNGs using JXL compression.

[Tafflad]

I have been using Adobe DNG converter as that was what Adobe forum advised I use.  I'm happy to try something else.

On point  4. The Media Info utility thinks that the Samsung DNGs are in invalid TIFF format. 

MediaInfo says the same 'invalid tiff' format for files converted by Adobe DNG conveter 

The diference was no Thumbnail until 'after' file had been openened ..... both variants of file lost the Thumbnail whan moved to MyPictures folder

[John R Ellis]

"I have been using Adobe DNG converter as that was what Adobe forum advised I use.  I'm happy to try something else."

You should update to the latest version of Adobe DNG Converter, as detailed in my item 8.

[Tafflad]

>6. You didn't provide a sample problem Samsung DNG.  Please upload one to Dropbox.

https://www.dropbox.com/scl/fi/uo7ny3y11jw91slc3n6lm/20240101_122721.dng?rlkey=wp9ad4kcwmwndj8nbdceh...

[Tafflad]

As DNG files have Thumbnail OK on desktop ... but removed when moved to subfolder in My Pictures .... could it be the folder attributes for 'My Pictures' are not optimal to allow DNG

[John R Ellis]

"could it be the folder attributes for 'My Pictures' are not optimal to allow DNG"

Triple-check the File Explorer options for the folder containing the DNG, as you described in your first post (those are the right options). 

Try making a test folder under Documents, setting its options to show thumbnails. Does the test folder display the DNG thumbnails?

[Tafflad]

>Try making a test folder

I'll try that

[Tafflad]

A lightbulb has come on.,  (maybe)

I created a new folder under 'My Pictures'

As soon as I copied in the test file form camera it  appeared with Thumbnail, but not the other.

It would suggest that there is something amiss with folder attributes .... anybody aware of a way to to fix ? ...... 

Can I force attributes of this 'new' folder to be applied to all folders within 'My Pictures'

[John R Ellis]

My Windows 11 File Explorer also shows thumbnails for the Samsung DNG too, as does Mac Finder.

[Tafflad]

#8  Your Adobe DNG converter is version 11.2, five years old. 

I have now done so ... it shows as 16.1

[Tafflad]

On another forum it advises to download the Adobe DNG Codec for windows ... but the link:

http://www.adobe.com/support/downloads/detail.jsp?ftpID=5495

is a dead one.

Do I need to install that Codec ?

[John R Ellis]

Adobe stopped supporting its Windows File Explorer codecs many, many years ago. When I was running Windows 10 (as recently as a year ago), I don't recall issues with DNG thumbnails in File Explorer, nor can I find any relevant reports here.

Perhaps you have the very old Adobe codec installed or a codec from a third party that got installed years ago that's buggy with respect to newer DNGs. Unfortunately, it's very hard to get a list of the File Explorer image codecs that are installed (as opposed to video codecs).  You could Google for how to uninstall all File Explorer image codecs.

Given that some DNGs do display in File Explorer, that would rule out problems with File Explorer settings for particular folders.

You could try Ardfry Image's DNG codec, which appears to be still maintained. It's got a free trial. Years ago I had good experience with their codecs but have no idea how well-maintained they are now.

If you don't want to buy a codec, you might have to bite the bullet and upgrade to Windows 11.

[Tafflad]

Following advice to avoid going to W11 currently.
It's not a W10 issue anyway, as I have tested it on my W10 laptop and DNG files display thumbnails.

Looks like I have some W10 spefic problem on my PC ....  I did ask the same Q on Microsoft support, they answered that this is not a standard MS file format and I should log a fault with Adobe.    They did add that as there are a significant number of people reporting the same problem, to complete a MS feedback form - which I did.

[Tafflad]

As part of a test - I copied 2 x DNG with thumbnail and 2 x DNG without thumbnails to a USB stick  .... the ones without Thumbnails still had no Thumbnail on another W10 machines.

LightRoom on my PC does see the files as DNG and imports them happily into Library

Interesting observation ....

When I copy files to USB stick I get following for each file without a Thumbnail:

  

[Tafflad]

An update ... as a further test reconverted the DNG files with Adobe DNG converter  (16.1)    the files on the desktop have the correct Thumbnail.

When moved to 'Pictures' folder, thumbnail is stipped off.

[John R Ellis]

"as a further test reconverted the DNG files with Adobe DNG converter  (16.1)    the files on the desktop have the correct Thumbnail. When moved to 'Pictures' folder, thumbnail is stipped off."

Do these steps to narrow down whether the issue is with the particulare Pictures folder or some more general:

1. Make a test folder on the same disk as Pictures.

2. In File Explorer, double-check that the test folder's folder property Always Show Icons Never Thumbnails is unchecked.

3. Convert some new files to DNG with DNG Converter 16.1. 

4. Move those new DNGs to the test folder. Do you see the thumbnails in the test folder?

If you see the thumbnails, then there's something screwy going on with your Pictures folder in particular. If you don't see the thumbnails, then it's a more general issue than  that.

[Tafflad]

#1  done

#2  this is at the Explorer level, not on the individual folder ... it is set this way at Explorer level.  On new folder set folder type in properties as 'pictures'

#3 Create new files ..... Here is pic of them in a folder on desk top 

#4 Moved them to a new folder same drive as other 'picture' folder.    

The files no longer have Thumbnails   - see pic

I moved files to DropBox as a test ... icons stay as Thumbnails

The 'Picture' folder is stored on my E: Drive  (as are Music & Video folders)  The OS is on C: Drive.

It has been this way since W98  (to avoid eating up space on System drive)

[John R Ellis]

Windows 11 File Explorer has a somewhat different UI, which makes it a little harder for me to follow along.

That the issue occurs on the test folder rules out there is something particular to Pictures.  The Pictures folder is one of those special folders that can be relocated to different drives and over the years has been the cause of weirdnesses.  But since the issue is occurring in a vanilla folder, we can rule out Pictures-specific problems.

I'm sure you've seen there are many articles about thumbnails not appearing on Windows 10:

https://www.google.com/search?q=windows+10+file+explorer+not+showing+thumbnails&rlz=1C5CHFA_enUS1064...  

With such stubborn issues, sometimes the only practical alternative is to do fresh install of Windows, which sometimes works and often doesn't.