PRB: Primary Interop Assembly (PIA) install occurs the first time that you open a Microsoft Office document that is referenced by a managed code extension

If your Microsoft Word document or your Microsoft Excel workbook uses a managed code extension that you created by using Microsoft Visual Studio Tools for the Microsoft Office System, a delay may occur the first time that you open the document or the workbook. You may also receive a dialog box that prompts you for your Microsoft Office 2003 installation source the first time that you open the document or the workbook.

A delay may occur when you open the Word document or the Excel workbook if a Primary Interop Assembly (PIA) that is referenced by the managed code extension is set to Installed on First Use or to Install on Demand in Microsoft Office 2003 Setup. When Excel or Word demand-loads a PIA, there is no wait pointer or progress indicator during the install process. Before the PIA install on demand, Office Setup may prompt you for the location of your Office 2003 install source if Office Setup cannot locate your install source when you open the document or the workbook.

This behavior is by design.

To use Office 2003 Setup from Microsoft Windows Control Panel to check or to change the install state for an Office 2003 PIA, follow these steps:

1. In Microsoft Windows Control Panel, click Add or Remove Programs.
2. In the installed programs list, click Microsoft Office 2003.
3. Click Change.
   
   Microsoft Office 2003 Setup starts in maintenance mode.
4. In the Microsoft Office 2003 Setup dialog box, click Add or Remove Features, and then click Next.
5. In the Custom Setup dialog box, click Choose advanced customization of applications, and then click Next.
6. In the install features list, locate the .NET Programmability Support feature for the product or for the component that you referenced.
   
   Note The Office 2003 PIAs require Microsoft .NET Framework 1.1. If .NET Framework 1.1 is not installed, the .NET Programmability Support features are not available in Office Setup.
7. Click the .NET Programmability Support option drop-down list, and then click one of the following install states:
   • Run from My Computer- The PIA is installed on the local computer.
   • Installed On First Use- The PIA is not immediately installed on the local computer. Instead, the PIA is installed on demand.
   • Not Available- The PIA is not installed on the local computer.
8. Click Update to update your Office installation with your changes.

For more information, click the following article number to view the article in the Microsoft Knowledge Base: