PDF not displaying in preview with outlook

[Alan]

After installation of PDFShelltools, the iFilterDll for pdf is PDFShellTools.dll.
Outlook (2016) is using this to display pdf in the preview pane within Outlook but it will not display correctly as it only opens a very small window, which cannot be enlarged.

Any advice please?

[RTT]

The IFilter extension provides access to the files text content, for direct or indexation search services, so the problem you are reporting would be related to the preview handler extension instead.
I just tested it, Outlook 2016 on Win10, and the preview handler is resizing correctly to the full boundaries of the outlook preview pane. In what Windows version are you experiencing this problem? What are your screen resolution and DPI settings?

Using the PDF-ShellTools manager, you may disable the "Preview Handler Tools" extension, and your system registered PDF preview handler will revert back to your previous, before PDF-ShellTools, PDF previewer. You are going to lose the preview handler tools functionality, but all the other PDF-ShellTools shell extensions will remain functional.