Can't see thumbnail images in Windows Explorer SOLVED

[dwg11]

This is a bit hard to figure out.

Bear with me.

Recently, in Windows Explorer, the thumbnail images for PDF files can't be seen.

1. Typical solution of settings in Adobe are correct.
Edit/Preferences/General/Enable PDF thumbnail previews in Windows Explorer is checked (on)

2. PDF-XChange Editor is normally the default, noticed when having Preview Pane on in Windows Explorer, the message is "This file can't be previewed because of an error in the SumatraPDF Preview (*.pdf).
Sumatra PDF was removed recently.

3. Tried to make Bluebeam Revu as the default (in windows Settings/Choose default applications by file type) and this time the thumbnails previews worked.
Changed back to PDF-XChange Editor, went to another folder and no good.

4. Went to settings in PDF-XChange Editor ... File/Preferences/File Associations/Thumbnail Handler for PDF files ... whatever I choose it won't let me change

Operating System is Windows 10.

How can it be fixed?

[Daniel - PDF-XChange]

Hello, dwg11

Just to clarify, Your intro and title here mention "thumbnails" but your testing and description seem to focus on the "preview" handler... These are two separate items, though both would be controlled by our shell utility. It is worth noting that to make changes, you often need to use the utility and set things to "none" then apply, before you can reset them to the desired item.

Following that, in some cases, a system restart can be required, as the window Shell is not always the most "runtime editable" item.
This article details the process of properly re-registering our shell extensions, as well as CMD options to use if the shell utility does not work.
https://www.pdf-xchange.com/knowledgeba ... extensions

Finally, regarding thumbnail exclusively, these are also cached by windows itself, depending on what was used in the past, the old thumbnails may remain present without allowing us to overwrite them. To rectify this, please see this article:
https://www.pdf-xchange.com/knowledgeba ... ails-cache

Kind regards,

[dwg11]

Thanks Daniel, yes it is for thumbnails, but in trying to sort it out noticed something relevant to SumatraPDF.

The change with utility seems to be working.

Yesterday updated Adobe and for a while some of the folders but not all, were showing thumbnail images, but not today, prior to using utility.

[Daniel - PDF-XChange]

Hello, dwg11

Unfortunately some application (or even windows) updates can cause changes to these items silently in the background. Adobe will steal the preview and thumbnails from us on occasion (I experience this myself once every few months, having their software installed locally for comparison testing).

Sadly there is little to be done in those cases except manually re-register the shell extensions correctly, which is part of why we made this utility. I am glad to hear it has worked for you so far.

Kind regards,