Windows Tools

Msizap.exe: Windows Installer Zapper

Overview | Notes | Syntax | Examples | Related Tools Open Command Prompt

This command-line tool deletes configuration data that Windows Installer maintains for products that it installs, including the directories, files, registry subkeys, and registry entries in which Windows Installer stores configuration data. You can use Msizap to remove remnants of corrupted Windows Installer installations that prevent you from installing a product correctly.

You can also use Msizap to give Adminstrators Full Control permissions to Windows Installer folders, files, and registry subkeys.

Msizap is designed as a last resort tool to be used only when conventional methods of repairing or removing an installation have failed. Before using Msizap, use Add or Remove Programs to remove or repair the installation. If that fails, use the Windows Installer Cleanup Utility (Msicuu.exe), which runs Msizap, but prevents you from causing unnecesary harm to the system.


You can use Msizap to correct the following installation failures.


Windows Installer manages the installation and removal of applications on Windows XP Professional. Typically, these installations conclude successfully, or are successfully reversed ("rolled back") or repaired. However, in rare situations, an installation, a rollback, or an uninstallation fails, leaving installation files and registry entries that would otherwise be removed. As long as these objects remain on the system, Windows Installer considers the installation to be active and incomplete.

Because Windows Installer conducts only one installation at a time, it will not start another installation until all indicators of the active installation are removed.

You can use Msizap to remove particular installation remnants, such as the InProgress registry subkey and the rollback registry data. You can also delete all configuration data for a specified installation, or all Windows Installer installations on the system.

System Requirements

File Required