The add-in loads and functions fine if I manually add it via
"Tools\Customize\Rearrange Commands", so it does appear to function at
least.

Here's the registry settings under Addins.

HKLM\SOFTWARE\Microsoft\VisualStudio\8.0\Addins\AddIn_NET.Connect\CommandPreload
= 1
HKLM\SOFTWARE\Microsoft\VisualStudio\8.0\Addins\AddIn_NET.Connect\LoadBehavior
= 1
HKLM\SOFTWARE\Microsoft\VisualStudio\8.0\Addins\AddIn_NET.Connect\FriendlyName
= "Formal Add In Name"
HKLM\SOFTWARE\Microsoft\VisualStudio\8.0\Addins\AddIn_NET.Connect\SatelliteDLLName=AddIn_NETSatellite_2005.dll
HKLM\SOFTWARE\Microsoft\VisualStudio\8.0\Addins\AddIn_NET.Connect\SatelliteDLLPath=C:\Program
Files\Microsoft Visual Studio 8\Common7\IDE

Under PreloadAddinState:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\8.0\PreloadAddinState\AddIn_NET.Connect=1

Perhaps, the code could stand improvement - although it functioned before.
We're using DTE.CommandBars.AddControl(), but the code doesn't make it that
far.  It does not get past "if(ConnectMode ==
AddInDesignerObjects::ext_cm_UISetup)" below.  If I comment that out,
DTE.Commands.AddNamedCommand() fails - probably because it is not at the
proper ConnectMode.  I can debug the 2002/2003 version to see what it used
to do if needed.

Here's OnConnection():

#define IfFailGoCheck(x, p) { hr=(x); if (FAILED(hr)) goto Error; if(!p) {hr
= E_FAIL; goto Error; } }

STDMETHODIMP CConnect::OnConnection(IDispatch *pApplication,
AddInDesignerObjects::ext_ConnectMode ConnectMode, IDispatch *pAddInInst,
SAFEARRAY ** /*custom*/ )
{
   AFX_MANAGE_STATE(AfxGetStaticModuleState())
   HRESULT hr = S_OK;
   m_pApplication = pApplication;
   pApplication->QueryInterface(__uuidof(EnvDTE::_DTE), (LPVOID*)&m_pDTE);
   pAddInInst->QueryInterface(__uuidof(EnvDTE::AddIn),
(LPVOID*)&m_pAddInInstance);

   if(ConnectMode == AddInDesignerObjects::ext_cm_UISetup)  // Does not get
this far unless commented out.
   {
       hr = S_OK;
       CComPtr<EnvDTE::Commands> pCommands;
       CComPtr<Office::_CommandBars> pCommandBars;
       CComPtr<Office::CommandBarControl> pCommandBarControl;
       CComPtr<EnvDTE::Command> pCreatedCommand;
       CComPtr<Office::CommandBar> pMenuBarCommandBar;
       IfFailGoCheck(m_pDTE->get_Commands(&pCommands), pCommands);

       // Fails with invalid argument.
       if(SUCCEEDED(hr = pCommands->AddNamedCommand(m_pAddInInstance,
CComBSTR("AddIn"),
          CComBSTR("Formal Add In Name"), CComBSTR("Formal Add In Name"),
VARIANT_FALSE, 1, NULL,
          EnvDTE::vsCommandStatusSupported+EnvDTE::vsCommandStatusEnabled,
&pCreatedCommand)) &&
          (pCreatedCommand))
       {
           try
           {
                // This code had to be changed slightly to compile in
VS.Net 2005:
                if ((hr =
m_pDTE->get_CommandBars((IDispatch**)&pCommandBars)) != S_OK)
                   throw hr;
                if ((hr = pCommandBars->get_Item(CComVariant(L"Tools"),
&pMenuBarCommandBar)) != S_OK)
                   throw hr;
                if ((hr = pCreatedCommand->AddControl(pMenuBarCommandBar,
1, (IDispatch**)&pCommandBarControl)) != S_OK)
                   throw hr;
         }
         catch (int i)
        {
                  return i;
         }
         catch (_com_error err)
        {
             ::MessageBox(NULL, err.ErrorMessage(), "ERROR", IDOK);
         }
   }
   return S_OK;

}
Error:
return hr;
}

Thanks, Jackie

I tried DTE.Commands.AddCommandBar, and it works fine in VS.Net 2005.
Thanks.