Is there possibility to deny printing/exporting option in Preview? API allows to disable buttons in preview - LlViewerProhibitAction [vbPrintPage,vbPrintAll,vbSendTo,vbSaveAs,vbViewPage] and limit export outputs LlSetOptionString(LL_OPTIONSTR_EXPORTS_ALLOWED_IN_PREVIEW, ‘PRV’). But still in preview windows user can press ctrl + p and print file to Micorosoft Print to PDF and create pdf file.
you can try to use
In VB.NET it looks like (convert hex 0x4000 to decimal):
'MenueID PrintAllPages = 113 LL.Core.LlViewerProhibitAction(113 + 16384)
Please note that it has no effect on already existing preview files, which are opened with the viewer LlView24.exe.