I cant view pdf thumbnails and acrobat does not give me an option to in preferences.

[kinnan.hamilton]

I cant find anywhere that shows me how to enable thumbnails preview for pdfs on mac opersting system. attached is a screenshot of my preferences on the left and the 'how to' instructions on the right. as you can see I have no box to tick that enables preview thumbnail....whyyyy

[ls_rbls]

"Thumbnail Preview in Windows Explorer" is a feature in the Acrobat Pro preferences that integrates with the Microsoft Windows operafing system's shell.

MacOS doesn't have Windows Explorer, that is unique to MS Windows environment.

I don't see the equivalent nor the same integration to that  viewing preference in macOS for the user(s) to take advantage of the Preview app.

I don't have macOS, so I am not sure if, in the case of macOS, the users need a third party plugin to handle that viewing preference.

[Bernd Alheit]

The instructions are for MS Windows.

[Luke Jennings3]

The thumbnail preview on a Mac can be controlled by your desktop view options (Command + J). If your previews are still missing, you may need to check for software updates and possibly restart your Mac.

This is a bit off topic, but you can change the image used for the thumbnail for a file or folder, open an image you want to use for the thumbnail in Apple Preview or Photoshop, select it and copy it to the clipboard, do a get-info on the file (Command + i), select the icon of the folder at the upper left, paste the clipboard contents into it.

[Luke Jennings3]

Upon further examination, it looks like you can optimize the PDF to remove the thumbnail, however, the preview remains with the file on my desktop, even though the preview in "get-info" has turned into a generic Acrobat icon, (probably because Acrobat is my chosen default PDF viewer). I assume Mac is creating its own thumbnail view where none exists. If your files were created with a generic Acrobat icon, Mac will use this instead of the image in the file. This may explain what you are seeing. Is the preview missing for all of your PDFs? 

Edit: Actually, Mac may show the generic icon if the view preference is set to the smaller size, by changing the preference to the large size, all icons show the page contents correctly.