Problem showing .msg preview handler with Windows 10 and Outlook 2013

Hi,


I am trying to activate the preview handler of the .msg files in my Delphi-Application (Delphi 10.1.2).


Running the program under Windows 7 and Windows 8.1 with Office 2013 works fine.

But with Windows 10 and Office 2013 it doesn´t work.


The preview of .doc, .xls ... works fine in all OS only the .msg shows only a gray panel.


I searched the internet for a solution but found nothing helpful. Most registry entries I found to check are okay or seem so.


The preview in Windows-Explorer works fine, too !!!



I use the following code to get the CLSID of the preview handler.


Res := AssocQueryString(
ASSOCF_NOTRUNCATE or ASSOCF_INIT_DEFAULTTOSTAR,
ASSOCSTR_SHELLEXTENSION,
'.msg',
'{8895B1C6-B41F-4C1C-A562-0D564250836F}', // GUID of IPreviewHandler
Buffer,
@bufsize
);



The CLSID seems to be correct.



Then I use the following code to show the preview:


FPreviewGUIDStr = Buffer;

if FPreviewGUIDStr='' then exit;

if FFileStream<>nil then
FFileStream.Free;

LPreviewGUID:= StringToGUID(FPreviewGUIDStr);
FPreviewHandler := CreateComObject(LPreviewGUID) As IPreviewHandler; // IPreviewHandler fomr ShlObj
if (FPreviewHandler = nil) then
exit;

SHCreateItemFromParsingName(PChar(FileName), nil, StringToGUID(SID_IShellItem), LShellItem);
LInitializeWithItem.Initialize(LShellItem, 0);

prc := ClientRect;
FPreviewHandler.SetWindow(Self.Handle, prc); // now I have only a blank panel



There is no error message, all code seem to work fine !!!


I hope there is someone having the same problem, so we could find a solution.



regards

Erik