I've built a C# .NET app that uses the Adobe ActiveX control to display a PDF.

It relies on a couple DLLs that get shipped with the application. These DLLs interact with the locally installed Adobe Acrobat or Adobe Acrobat Reader installed on the machine.

This app is being used by some customer already and works great for nearly all users ( I check to see that the local machine is running at least version 9 of either Acrobat or Reader already ).

I've found 3 cases where the app returns the error message "Error HRESULT E_FAIL has been returned from a call to a COM component" when trying to load (when the activex control is loading).

I've checked one of these user's machines and he has Acrobat 9 installed and is using it frequently with no problems. It does appear that Acrobat 7 and 8 were installed at one time since there are entries for them in the registry along with Acrobat 9.

I can't reproduce this problem locally, so I am not sure exactly which direction to go.

The error at the top of the stacktrace is: System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component.

Some research into this error indicates it is a registry problem.

Does anyone have a clue as to how to fix or work around this problem, or determine how to get to the core root of the problem?

The full content of the error message is this:

System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component.    at System.Windows.Forms.UnsafeNativeMethods.CoCreateInstance(Guid& clsid, Object punkOuter, Int32 context, Guid& iid)    at System.Windows.Forms.AxHost.CreateWithoutLicense(Guid clsid)    at System.Windows.Forms.AxHost.CreateWithLicense(String license, Guid clsid)    at System.Windows.Forms.AxHost.CreateInstanceCore(Guid clsid)    at System.Windows.Forms.AxHost.CreateInstance()    at System.Windows.Forms.AxHost.GetOcxCreate()    at System.Windows.Forms.AxHost.TransitionUpTo(Int32 state)    at System.Windows.Forms.AxHost.CreateHandle()    at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)    at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)    at System.Windows.Forms.AxHost.EndInit()    at AcrobatChecker.Viewer.InitializeComponent()    at AcrobatChecker.Viewer..ctor()    at AcrobatChecker.Form1.btnViewer_Click(Object sender, EventArgs e)    at System.Windows.Forms.Control.OnClick(EventArgs e)    at System.Windows.Forms.Button.OnClick(EventArgs e)    at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)    at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)    at System.Windows.Forms.Control.WndProc(Message& m)    at System.Windows.Forms.ButtonBase.WndProc(Message& m)    at System.Windows.Forms.Button.WndProc(Message& m)    at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)    at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)    at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)