InstallShield 2012 Express Edition User Guide - Knowledge Base ...

Chapter 9: Configuring the Target System
Per-User vs. Per-Machine Installations
During a per-machine installation, the Windows Installer requires elevated privileges, and it directs files
and registry entries to per-machine locations. If User Account Control (UAC) is available on the target
system, a per-machine installation typically prompts for consent or credentials, depending on the access
level of the user. During a per-user installation, the Windows Installer does not prompt for credentials,
and it redirects files and registry entries to per-user locations.
For more information, see Single Package Authoring on the MSDN Web site.
Effects of ALLUSERS on Windows Vista and Later
Custom actions that have an in-script execution setting of deferred in system context are used to
perform an action with the rights granted to the LocalSystem account on Windows, since the Windows
Installer service runs in the system context. Actions not marked as deferred in system context run with
user impersonation and have the rights that the user who launches the installation has.
When a per-user installation (that is, one where ALLUSERS is not set) is run, deferred-in-systemcontext
actions run in the same context in which normal deferred or immediate custom actions run,
which is with user impersonation. This can potentially cause a run-time issue with the custom action in
the following circumstances:
• The user who launches the Windows Installer installation is not an administrator; or the user is
running the installation on Windows Vista or later, the user is part of the Administrators group, and
the user does not have administrator privileges by default.
• The custom action attempts to modify a resource in a per-machine location on the machine, such as
a file in the Program Files folder, or a registry key or value in HKEY_LOCAL_MACHINE.
While this may not be an issue with Windows XP or earlier versions of Windows, Windows Vista and
later do not give users full administrator privileges by default. Therefore, since a deferred-in-systemcontext
action runs with user impersonation when ALLUSERS is not set, the custom action could fail.
The recommended method for preventing this behavior is to ensure that a per-machine installation is
always performed by setting ALLUSERS. Per-machine installations are generally easier to manage
than per-user installations.
Default Value of ALLUSERS
The ALLUSERS property is set to 1 by default. If you configure your installation so that it can be
installed per user without administrative privileges, you may want to consider changing the value of the
ALLUSERS property.
Task To configure the value of ALLUSERS:
1. In the View List under Organize Your Setup, click General Information.
2. For the ALLUSERS setting, select the appropriate value.
For information about the available options, see General Information Settings.
Default Controls on the Ready to Install and Customer Information Dialogs
Use the Show All Users Option setting to specify whether you want to give end users the option of
installing your product for all users or for only the current user. This setting is displayed when you click
the Dialogs explorer in the Dialogs view. Available options for the Show Per-User Option setting are:
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