InstallationImpact Enumeration


Applies To: Windows Server Update Services

Defines constants that indicate the possible impact an update may have on the computer or on other applications that are running on the computer.

Namespace:   Microsoft.UpdateServices.Administration
Assembly:  Microsoft.UpdateServices.Administration (in Microsoft.UpdateServices.Administration.dll)

public enum InstallationImpact

Member nameDescription

Specifies that the Update qualifies as a "zero service interruption" (ZSI) Update. Installing/uninstalling a ZSI Update results in negligible impact on the system. This is the desired behavior for all Updates. The Update must meet stringent requirements to qualify for this rating, including but not limited to: it must not perform or require a reboot, it must not display any UI, and it must install/uninstall successfully even if it affects an application or service that is currently in use. Updates that qualify for this rating may be eligible for special handling within MSUS, such as accelerated distribution.


Specifies that installing/uninstalling the Update will result in the level of impact to the system that is typical to most updates. This means, in essence, that the update does not qualify for any of the special impact ratings defined below.


Specifies that installing or uninstalling the update results in such a high impact to the system that it must be installed "exclusively". This means the MSUS Client will install or uninstall this Update by itself without batching it together with others. Update authors should avoid authoring exclusive Updates if at all possible. Exclusive Updates typically reboot during or after installation (although it is permitted to author an exclusive Update that does not reboot). Exclusive Updates may face restrictions in how they may be distributed.

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