Reducing application launch time

Use the session pre-launch feature to reduce application launch time during normal or high traffic periods, thus providing users with a better experience. The pre-launch feature allows a pre-launch session to be created when a user logs on to Citrix Workspace app, or at a scheduled time if the user is already logged on.

This pre-launch session reduces the launch time of the first application. When a user adds a new account connection to Citrix Workspace app for Windows, session pre-launch does not take effect until the next session. The default application ctxprelaunch.exe is running in the session, but it is not visible to you.

Session pre-launch is supported for StoreFront deployments as of the StoreFront 2.0 release. For Web Interface deployments, be sure to use the Web Interface Save Password option to avoid logon prompts. Session pre-launch is not supported for Citrix Virtual Apps and Desktops deployments.

Session pre-launch is disabled by default. To enable session pre-launch, specify the ENABLEPRELAUNCH=true parameter on the Workspace command line or set the EnablePreLaunch registry key to true. The default setting, null, means that pre-launch is disabled.


If the client machine has been configured to support Domain Passthrough (SSON) authentication, pre-launch is automatically enabled. If you want to use Domain Pass-through (SSON) without prelaunch, set the EnablePreLaunch registry key value to false.

The registry locations are:

  • HKEY_LOCAL_MACHINE\Software\[Wow6432Node\]Citrix\Dazzle

  • HKEY_CURRENT_USER\Software\Citrix\Dazzle

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. Typically used for normal traffic periods. A user can trigger just-in-time pre-launch by restarting the Citrix Workspace app.
  • 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 used for high-traffic periods.

Configuring pre-launch on a Citrix Virtual Apps 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” in the Citrix Virtual Apps and Desktops documentation for information about configuring session pre-launch on the Citrix Virtual Apps server.

You cannot customize the pre-launch feature using the receiver.admx file. However, you can change the pre-launch configuration by modifying registry values during or after Citrix Workspace app for Windows installation.

  • The HKEY_LOCAL_MACHINE values are written during client installation.
  • The HKEY_CURRENT_USER values enable you to provide different users on the same machine with different settings. Users can change the HKEY_CURRENT_USER values without administrative permission. You can provide your users with scripts to accomplish this.

HKEY_LOCAL_MACHINE registry values

For Windows 7 and 8, 64-bit: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\ICA Client\Prelaunch

For all other supported 32-bit Windows operating systems: HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Prelaunch

Name: UserOverride


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


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 configured for Schedule.)

Name: Schedule


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 registry values


The State and Schedule keys have the same values as for HKEY_LOCAL_MACHINE.

Reducing application launch time