Windows 10: [SOLVED] PDF Thumbnail images NOT SHOWING in in subfolders

Windozer10 1909, 2004
RAM 32gb
Intel i7 6700

Problem:
Thumbnail images of PDF files within sub-folders of a folder one day stopped to show. (image2 "The sub-folders with PDF icons.jpg") Only PDF icons, while when opening the folder I can see all the thumbnails (Imge1 "The PDF files.jpg").

Facts:
These are one of many very odd bugs in Windows 10 that are buried somewhere so deep in the registry that nobody can ever find them. Certainly not Microsoft themselves and their utterly inept "support answers" are a bad joke at best.
The bug like so many in these flawed Microsoft products if not all, lies buried in the registry somewhere deep and despite having spent hours I have not been able to find exactly which particular entry causes it.
So instead of all the mindless generic help everywhere in the tyle of "if all fails to un-jam the front door in the house just tear down the house and rebuild it." Here is (a) solution:

Observation:
Since I recently upgraded Adobe Acrobat I suspect strongly that their poorly executed non intuitive bloatware app is the culprit by having changed something in the registry. But to find that is a futile attempt at best.

In the beginning the issue was that all older PDF files, created or opened with the prior version, just showed a large PDF icon symbol whereas the ones with the newer version produced the thumbnail image.

Upon opening older PDF files and implementing a minute change on the document and then undoing that change, if needed, so that I could re-save the document, the icon image disappeared and the thumbnail image of the document was here again.

In a somewhat relevant but different behavioral way it is the same issue with the preview of thumbnail images within subfolders icons.

How to fix it:
If you change on a PDF file in any given subfolder just one character in the file name, or add or remove a space and re-save/overwrite the file with the "new' name, the PDF thumbnail image previously missing in the subfolder appears now! (image3: "Problem solved.jpg")



PS: Just to mention about another Windows 10 saga:
Last year I had an issue that suddenly my tool bar group menu structure I had sorted to my needs suddenly auto-sorted. Nobody knew nobody could figure it out. (I spare you the description of the suggestions I got to "fix" it, never mind getting someone to understand in the first place what I was talking about)

By accident, "slip of the hand with the mouse" I discovered how to restore it. And despite running registry difference apps I was unable to find which entry changed respectively restored it.
(Taskbar Toolgroups used to retain menu order) My finding answer #10.












:)

 

File Explorer - Some PDF's show thumbnail image, some don’t

In Windows 10 File Explorer, I see thumbnails for a few of my pdf files but still see the generic Adobe pdf icon for most of them.

• In Windows 10 folder options, the checkbox for “Always show icons, never thumbnails” is unchecked.
• On the Adobe Reader preferences general tab, “Enable PDF thumbnails previews in Windows Explorer” is checked.
• Adobe Acrobat is set as my default PDF viewer.
• I have used Disk Cleanup to delete all my thumbnails to clear and rebuild the cache, yet the problem persists.

Any suggestions on how I can see all the pdf icons as thumbnails?
Windows 10 Pro, Version 1903, Build 18362.657
Adobe Acrobat Reader DC (20.006.20034)

I asked over in the Adobe Acrobat Reader forum a few days ago but have received no replies.





Ron

 

File Explorer - Some PDF's show thumbnail image, some don’t

Other than this how to from Adobe - Enable thumbnail preview of PDFs in Windows Explorer. I've no other suggestions as that fix should be working. Why it's not is a mystery.

BTW the image I posted showing the previews in Acrobat is from the folder placed in my OneDrive folder so that's not the issue.

And the link above does apply to Adobe Acrobat Reader DC, so.... *Confused

 

PDF files_ Some show thumbnail image, some don't?

I am having this problem with PDF files. Some of them show the 1st page of the file(mostly books front cover) as thumbnail image on the desktop, and, inside folders, but, some don't show the thumbnail image of the first page in the file. These files that don't show the thumbnail image, just show the same standard icon of the program that is used to open the PDF files.For example, I am using PDF-Xchange program for PDF files right now. So, these files just show a PDF file Icon for that program. I do not know what is causing some files to show the thumbnail images, but, others don't. It helps me a lot if I can see the 1st page of the file(mostly Books Front covers) as a thumbnail image. I appreciate any help with this issue. Thanks in advance.