I'm writing a C# program that acts as a PowerPoint 2007 plugin. On some machines, some calls to the PowerPoint object model throw a COMException with the message RPC_E_SYS_CALL_FAILED. I couldn't find any specific advice on what to do regarding this error, or how to avoid it. From Googling it looks like something to do with the message queue or Single-Threaded Apartments. Or am I way off?
Example of the error message is:
System call failed. (Exception from HRESULT: 0x80010100 (RPC_E_SYS_CALL_FAILED))
at Microsoft.Office.Interop.PowerPoint._Presentation.get_FullName()
Unfortunately, the problem is occurring on a client's machine, so I have no easy way to debug it! Should I just retry the calls whenever I get this error?
Any advice to help me resolve this problem would be greatly appreciated!
I don't know it is related to your problem, but all your COM calls must come from within the same thread your add-in was created on. If you created new threads you must take special care. Details are described in these two articles:
are you making the call from a thread with its ApartmentState set? if not, that might be the culprit - COM interop is pretty finicky about that sort of thing
What are the security settings of the client? It is quite possible that the security settings of the client (either Windows/OS settings or PowerPoint/App settings) won't allow your plug-in to communicate via RPC.
This can very easily happen if you make any calls to the Powerpoint object model from a background thread. One plausible scenario is having a timer that periodically checks some sort of status value. If, when the timer fires, Powerpoint is busy (for example a dialog box is open) the call will fail.
This Microsoft article gives an overview of threading support in Office: http://msdn.microsoft.com/en-us/library/8sesy69e.aspx
来源：https://stackoverflow.com/questions/99271/c-sharp-com-office-automation-rpc-e-sys-call-failed