System Shutdown Reason Codes (Reason.h) - Win32 apps (original) (raw)

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System Shutdown Reason Codes

• Article
• 01/07/2021

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The shutdown reason codes are used by the ExitWindowsEx and InitiateSystemShutdownEx functions in the dwReason parameter.

A maximum of MAX_NUM_REASONS reason codes will be processed by the system. MAX_NUM_REASONS is defined in reason.h.

The following are the major reason flags. They indicate the general issue type.

The following are the minor reason flags. They modify the specified major reason flag. You can use any minor reason in conjunction with any major reason, but some combinations do not make sense.

The following optional flags provide additional information about the event.

Remarks

The following combinations are recognized by the system. The table indicates the string that is displayed in the Shutdown Event Tracker, and provides a more detailed description. The default string is "No title for this reason could be found."

You can also define your own shutdown reasons and add them to the registry. Each reason code should be stored as a registry value in the following key:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Reliability\UserDefined\<default_system_language_ID>

This key contains value names of the following form: xxxxx;nnn;nnnnn. The semicolons delimit the components of a value name.

xxxxx

One to five of the following control flags (no other characters can be used).

The order in which the flags are used is not important. For example, CSP indicates a planned shutdown where the expected shutdown dialog box is displayed, and a comment is required.

nnn

Major reason. This component must be a number in the range 64-255. The range 0-63 is reserved for use by the system.

nnnnn

Minor reason. This component must be in the range 0-65535.

Custom reasons are sorted in the user interface by major reason number, then by minor reason number. No two custom reasons can use the same major and minor reasons, unless one is planned and the other is unplanned. Otherwise, the system will use the first instance and ignore the others.

The data for each registry value is two strings, separated by \n\r. The first string is a title string to be displayed in the shutdown dialog box, and written to the event log. The maximum size is 64 characters. Title strings must be unique. Custom titles cannot match the standard titles defined by the system, or another custom title. The second string is a description string to be displayed in the shutdown dialog box; it is optional. The maximum size is 256 characters.

Requirements

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