I have created the necessary manifests for my COM server DLL and a client application to work registration-free in Windows XP. I've tested all kinds of combinations (with and without a registration) and in all cases the client application sees the side-by-side version of the library if the manifests are present, and the registered one if not (or a COM error if there is no registration at all). I've tested on my Windows XP development machine, and given the files (DLL, client EXE and one manifest for each) to co-workers, who've also run everything successfully on their own Windows XP machines. The manifests are external XML files, not embedded resources. So far, so good.
However, when I copy the files to a Windows Server 2003 machine, it doesn't work. I get a silent failure, but an application error in the Application Event Log (see below). If I unregister the DLL and remove the manifests, I get a similar error (silent at the command prompt, but an application error in the event log). Obviously there is some problem finding the registration. I have reproduced this on every Windows Server 2003 machine I can access at our company. According to the Microsoft documentation on side-by-side/registration-free COM, it's supposed to work on Windows XP and later, and Windows Server 2003 and later.
To be clear, the same client runs perfectly on those same Windows Server 2003 machines against a registered (i.e., using regsvr32) version of the same COM DLL, under the same login credentials I'm trying to use for registration-free COM. In other words, there are no intrinsic issues masquerading as registration-free COM problems – this client and server operate fine when the server is registered globally in the registry.
Anybody have any ideas of how to investigate further? I'm not an expert on Windows Server, but is there perhaps some policy setting that would need to be changed to enable this support? If I can locate the necessary change, our tech support/infrastructure people will probably have no probably doing it, but I can't rely on them to research the issue too as they are swamped.
In case it matters (I don't think it should, but you never know) the DLL is written in Delphi 2007, while the client is written in Visual C++.
Event Type: Information Event Source: Application Error Event Category: (100) Event ID: 1004 Date: 5/2/2009 Time: 8:07:45 AM User: N/A Computer: ***server name**** Description: Reporting queued error: faulting application ***program name***.exe, version 0.0.0.0, faulting module ***program name***.exe, version 0.0.0.0, fault address 0x0002ac9e. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Best Answer
One thing to look for is that whether the exe has an internal manifest. In XP, the exe manifest search order is external then internal. In Server 2003 and later, the order is internal then external.