Question

I am facing a situation here and would like some feedback or advice.
I have been given an application that run as a service, with a specific service account (not admin on the server), and try to open an Excel workbook.

The problem is not with the initial application, as I can reproduce it with the generic C# code below (embedded in a service structure):

try{
    this._exApp = new Microsoft.Office.Interop.Excel.ApplicationClass();
    this._exApp.Visible = false;

    Log.Logger.Info("Opening workbook...");
    Workbook workbook = this._exApp.Workbooks.Open(
                thisFileName,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing,
                Type.Missing
                );
    Log.Logger.Info("Workbook opened!");

    //Do something with the result
    Log.Logger.Info("Closing workbook...");
    workbook.Close(false, thisFileName, null);
    Marshal.ReleaseComObject(workbook);

    this._exApp.Quit();
}
catch(Exception ex){
    Log.Logger.Error(ex.Message);
}

(nothing special about *this._exApp* and thisFileName, which are just respectively casted to a Microsoft.Office.Interop.Excel.Application, and as a string with the path of the file to open. Log.Logger is a a logger class using log4net to allow me seeing when the problem occurs)

The service is running as a service account, which is a user on the server, not an admin. It has access to the target file and to files on the server (as Read access). The server is a Windows Server 2003 Standard Edition SP2 (could not try yet on a 2008 R2 server).

The problem I am facing is that it just hangs when trying to open the workbook, so in terms of tracing the last line I have is “Opening workbook…”, never reaching the “Workbook opened” line. No exception is raised.

So the code is very simple, it is just trying to open an excel workbook. I have done already some investigations, and here are my findings:

• I know that Microsoft does not support a server side Excel automation, but I have been given the service as it, and do not have a choice about the technology used.
• I have configured all the Component Services/DCOM/Microsoft Excel Application security settings so that the service account has all the permissions possible.
• The service does the job correctly if the service account is local admin on the machine. This is not really on option for production.
• The service does the job correctly if the file it tries to open is a local file. Unfortunately, the file we tries to access is on a remote file server, and it does not work in that situation.
• The code above run from a command line with the same user on a remote file works fine, but not any more when run as a service.
• I have read about the C:\Windows\System32\config\systemprofile\Desktop bug, but the folder exists.
• Excel open correctly when lauched with the service account.

So basically, the situation is the Workbooks.Open method hangs when run as a service, under a service account that is not admin, and when accessing a remote file.

I would appreciate any input or idea on this topic.

Thanks.

Jonathan

EDIT: As per Matt’s workaround below, we have implemented a local copy of the remote file, so I am accepting it as an answer, but I remain interested in any suggestion on how to make it work directly on the remote file.

Answer 1

I would have put this as a comment, but I don’t have enough rep yet, so this is more just a possible workaround rather than a full blown answer…

The service does the job correctly if the file it tries to open is a local file. Unfortunately, the file we tries to access is on a remote file server, and it does not work in that situation.

Can you first copy the file from the remote server to a local temp location?

        this._exApp = new Microsoft.Office.Interop.Excel.ApplicationClass();
        this._exApp.Visible = false;

        string localFile = "local.xls";
        System.IO.File.Copy(thisFileName, localFile);

        Log.Logger.Info("Opening workbook...");
        Workbook workbook = this._exApp.Workbooks.Open(localFile, ...);
        Log.Logger.Info("Workbook opened!");