It seems that Adobe is unable to configure its system in a way that would let pdf documents being previewed in Windows Explorer like images or simple text documents can be previewed.
If you open the preview pane in Windows Explorer instead of a pdf preview you get an error in pdf preview handler.
You can fix this easily by installing a small freeware called PDF Preview for Windows 8. Note that the program is not that convenient when used as a standalone pdf viewer, but you don’t have to use it this way. Keep any viewer you already have, and just let this program fix the pdf handler errors.
The program installs a PDF Preview add-in for Windows Explorer, Microsoft Office, and Microsoft Outlook, and automatically configures itself to enable the preview of PDF files in the Preview pane of Windows Explorer or in the Reading pane in Outlook 2012, 2010, 2007.
It is designed for Windows 8, and works on both Windows 8 64-bit and Windows 32-bit systems.