問題：

var obj = Marshal.GetActiveObject("PowerPoint.Application") 

該代碼在管理員模式下運行無法正常獲取正在運行的 PPT PowerPoint.Application 對象，而在非管理員模式下可以正常獲取。

針對該問題，微軟的msdn官方文檔，也沒有給予說明。

https://docs.microsoft.com/zh-cn/dotnet/api/system.runtime.interopservices.marshal.getactiveobject?redirectedfrom=MSDN&view=netframework-4.7.2#%E5%AE%89%E5%85%A8%E6%80%A7

搜索資料：

https://stackoverflow.com/questions/23698462/marshal-getactiveobjectoutlook-application-throws-mk-e-unavailable-when-debu

懷疑 ：和用戶有關，沒有直接證據。

Marshal.GetActiveObject(“Outlook.Application”) throws MK_E_UNAVAILABLE when debugging with elevated privileges

This code run without problem in release r debug when Visual studio isn't started as an admin.

Marshal.GetActiveObject("Outlook.Application");

However, when I start Vs as administrator and run the same line in debug, I get the following error:

System.Runtime.InteropServices.COMException
Operation unavailable (Exception from HRESULT: 0x800401E3 (MK_E_UNAVAILABLE))

How can I fix this.

  answer :

I would guess that you are running Visual Studio as Administrator (started via Run as Administrator) while Outlook was opened as user, who was logged in as under Windows logon. So the Visual Studio is running under different user than Outlook client.