To pre-launch applications to user devices

Use the pre-launch feature to reduce application launch time at high-traffic periods. For example, if your environment includes a large number of users who launch the same application within a ten-minute time-frame, the rapid succession of logon requests can overwhelm servers and slow down application launch for all users. The pre-launch feature allows a pre-launch session to be created when a user logs on, or at a scheduled time if the user is already logged on. This pre-launch session reduces the launch time of the first application. The default application ctxprelaunch.exe runs in the session, but is not visible to the user.

Considerations:

• When a pre-launch session is created, it takes up a license immediately, even if the user does not launch an application.
• When you enable this feature for an application, the setting applies to all users and servers configured for the application; in addition, the pre-launch session created for the application is also available for all other published applications on the listed servers.

To customize the inactivity behavior for the pre-launch application, configure the Citrix User policy for Session Limits:

• Pre-launch Terminate Timer IntervalMaximum amount of time before the pre-launch application exits (60 minutes by default). Starting a user application in the session also terminates the pre-launch application. Once the pre-launch application exits, the session remains alive if the user’s applications are running or if you configured session lingering.

• Pre-launch Disconnect Timer Interval

  Amount of time before the pre-launch application disconnects the session (60 minutes by default). Once disconnected, the session gives up the XenApp license. When a user launches an application, the session is reconnected. This timer does not disconnect a session if a user launches an application. If the interval is not configured, the pre-launch session is not ever disconnected.

Note: Customizing the pre-launch feature using Administrative Templates is not supported. However, you can change the pre-launch configuration by modifying the registry values, located at:

• For 32-bit: HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Prelaunch andHKEY_CURRENT_USER\Software\Citrix\ICA Client\Prelaunch
• For 64-bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\ICA Client\Prelaunch

To enable the pre-launch session:

1. In the AppCenter, from the navigation pane, select the server.

2. From the Applications list, select an application.

   Note: Select an application that is published for the groups of users and servers that are eligible for the pre-launch session.

3. From the Actions pane, select Other Tasks > Create pre-launch application.

4. This task creates a copy of the application with all its properties, users, and servers, and PreLaunch precedes the application name. This “application” is not enumerated to users. Refer to the table below for the application properties that you can modify.

Properties and tasks for pre-launch applications

The following table lists the properties and tasks that are inherited or configured for pre-launch applications.

The application name, display name, description, and icon are visible only in the AppCenter and do not apply to the pre-launch application.

Inherited from the original application. Modifications are applicable for a pre-launch application.

Not applicable for a pre-launch application. Modifications are not used.

Properties:

• Enable/disable application
• Servers
• Users
• Location
• Access conditions
• Access gateway filters
• Client audio requirement
• Connection encryption requirement
• Encryption level
• Session window color depth

Properties:

• Hide disabled application: The application is always hidden.
• Application type: The type is always an installed application.
• Working directory: The directory is always set to Systems32 folder in XenApp installation location. You can change this by editing the pre-launch application properties.
• Client application folder: The pre-launch application is not listed on the user device.
• Add to client’s start menu: The pre-launch application is not visible on the user device.
• Add shortcut to client’s desktop: The pre-launch application is not visible on the user device.
• File types: The pre-launch application does not have any associated file types.
• Maximum instances: Always one instance per user.
• Allow only one instance of application for each user: Always only one instance of the pre-launch application. If you configure more than one pre-launch application of the server and user combination, additional instances are not launched.
• Application importance: The pre-launch application is always the first application launched.
• Session window size: The pre-launch application is not visible on the user device.
• Hide application title bar: The pre-launch application is not visible on the user device.
• Maximize application at startup: The pre-launch application is not visible on the user device.

Tasks:

• Disable/enable application
• Duplication application
• Move to folder
• Delete application
• Refresh user data
• Attach application to a load evaluator

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Reducing Application Launch Time

Use the session pre-launch feature to reduce application launch time during normal or high traffic periods; thus, giving the user a better experience. The pre-launch feature allows a pre-launch session to be created when a user logs on to Receiver, or at a scheduled time if the user is already logged on. This pre-launch session reduces the launch time of the first application. The default application ctxprelaunch.exe is running in the session, but it is not visible to the user.

There are two types of pre-launch:

• Just-in-time pre-launch. Pre-Launch starts immediately after the user’s credentials are authenticated whether or not it is a high-traffic period.
• Scheduled pre-launch. Pre-launch starts at a scheduled time. Scheduled pre-launch starts only when the user device is already running and authenticated. If those two conditions are not met when the scheduled pre-launch time arrives, a session does not launch. To spread network and server load, the session launches within a window of when it is scheduled. For example, if the scheduled pre-launch is scheduled for 1:45 p.m., the session actually launches between 1:15 p.m. and 1:45 p.m.

Typically, you can use just-in-time pre-launch for normal traffic periods and scheduled pre-launch for known high-traffic periods.

An example of a high-traffic period - if your environment includes a large number of users who launch applications during peak periods such as when users start work or return from lunch, the rapid succession of logon requests might overwhelm servers and slow down application launch for all users.

Configuring pre-launch on the XenApp server consists of creating, modifying, or deleting pre-launch applications, as well as updating user policy settings that control the pre-launch application. See To pre-launch applications to user devices for information about configuring session pre-launch on the XenApp server.

Caution: Editing the Registry incorrectly can cause serious problems that may require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.

Customizing the pre-launch feature using the icaclient.adm file is not supported. However, you can change the pre-launch configuration by modifying registry values during or after Receiver installation.

Receiver for Enterprise is a requirement for pre-launch.

Registry value for Windows 7, 64-bit

The value for Windows 7, 64-bit, is: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\ICA Client\Prelaunch.

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\ICA Client\Prelaunch - Enables different users on the same user device to have different settings. It also allows a user to change the configuration without administrative permission. You can provide your users with scripts to accomplish this.

Name: State

Values:

0 - Disable pre-launch.

1 - Enable just-in-time pre-launch. (Pre-Launch starts after the user’s credentials are authenticated.)

2 - Enable scheduled pre-launch. (Pre-launch starts at the time scheduled in Schedule.)

Name: Schedule

Value:

The time (24 hour format) and days of week for scheduled pre-launch entered in the following format:

HH:MM|M:T:W:TH:F:S:SU where HH and MM are hours and minutes. M:T:W:TH:F:S:SU are the days of the week. For example, to enable scheduled pre-launch on Monday, Wednesday, and Friday at 1:45 p.m., set Schedule as Schedule=13:45|1:0:1:0:1:0:0 . The session actually launches between 1:15 p.m. and 1:45 p.m.

Registry values for other Windows systems

The values for all other supported Windows operating systems are:HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Prelaunch andHKEY_CURRENT_USER\Software\Citrix\ICA Client\Prelaunch.

HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Prelaunch - Written at installation, with default values.

Name: UserOverride

Values:

0 - Use the HKEY_LOCAL_MACHINE values even if HKEY_CURRENT_USER values are also present.

1 - Use HKEY_CURRENT_USER values if they exist; otherwise, use the HKEY_LOCAL_MACHINE values.

Name: State

Values:

0 - Disable pre-launch.

1 - Enable just-in-time pre-launch. (Pre-Launch starts after the user’s credentials are authenticated.)

2 - Enable scheduled pre-launch. (Pre-launch starts at the time scheduled in Schedule.)

Name: Schedule

Value:

The time (24 hour format) and days of week for scheduled pre-launch entered in the following format:

HH:MM|M:T:W:TH:F:S:SU where HH and MM are hours and minutes. M:T:W:TH:F:S:SU are the days of the week. For example to enable scheduled pre-launch on Monday, Wednesday, and Friday at 1:45 p.m., set Schedule as Schedule=13:45|1:0:1:0:1:0:0 . The session actually launches between 1:15 p.m. and 1:45 p.m.

HKEY_CURRENT_USER\SOFTWARE\Citrix\ICA Client\Prelaunch - Enables different users on the same user device to have different settings. It also allows a user to change the configuration without administrative permission. You can provide your users with scripts to accomplish this.

Name: State

Values:

0 - Disable pre-launch.

1 - Enable just-in-time pre-launch. (Pre-Launch starts after the user’s credentials are authenticated.)

2 - Enable scheduled pre-launch. (Pre-launch starts at the time scheduled in Schedule.)

Name: Schedule

Value:

The time (24 hour format) and days of week for scheduled pre-launch entered in the following format:

HH:MM|M:T:W:TH:F:S:SU where HH and MM are hours and minutes. M:T:W:TH:F:S:SU are the days of the week. For example, to enable scheduled pre-launch on Monday, Wednesday, and Friday at 1:45 p.m., set Schedule as Schedule=13:45|1:0:1:0:1:0:0 . The session actually launches between 1:15 p.m. and 1:45 p.m.

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