Possibly you too use the preview pane available in Windows File Explorer: I find it very useful to check if the file I am looking for is the selected one!
I changed my PC and I noticed that the preview of every pdf file was not available. I installed the Adobe Reader Touch app from the app Store so I was a bit disappointed to have no more that feature I had in my old PC. Then I see that in that one I had associated with the pdf extension the Acrobat Reader DC application, so I realize why there was that different behavior.
So, after installing the Acrobat Reader DC application also on my new PC, I had again the preview of pdf files!! Therefore I suggest you to install the Acrobat Reader DC version of the Acrobat Reader and uninstall the Adobe Reader Touch one, if you already installed it!
In the following you can find the simple steps to install Acrobat Reader DC application: you need then to change the default application to use to open pdf files.
Now ì, whenever you select a pdf file in Windows File Explorer, its preview is displayed on the right if the View setting is set for having a Preview pane: