Support for Citrix Offline Plug-in 6.0

In order to provide support for Citrix Offline Plug-in 6.0, a driver is included in the EM User Virtualization Service software. The driver, called AsVfxLdr.sys, replaces the existing Windows AppInit_DLLs registry value for loading the personalization modules into managed processes. The driver enables better control over what is hooked and when.

For Citrix Offline Plug-in 6.0t all hooking is performed via a kernel based API and the driver enables Environment Manager’s hook DLLs to be loaded after the Citrix hooks, as part of the process initialization.

With the driver it is possible to exclude certain processes from having the personalization modules loaded by setting the following registry value on the client:

  • Key - HKLM\Software\AppSense\Environment Manager\AsModLdr\
  • Name - Exceptions
  • Type - REG_MULTI_SZ
  • Data - List of processes that should be ignored by the driver. The list should only contain the filename of the process including the file extension, e.g. calc.exe; full paths are ignored and will not be matched. The list is stored in multi-string format with each filename as a separate string. The driver will not attempt to load any DLLs into these processes.

It is also possible to disable the driver and revert to the existing AppInit_DLLs mechanism by setting the following registry value on the client:

  • Key - HKLM\Software\AppSense\Environment Manager\
  • Name - LegacyAppInit
  • Type - REG_DWORD
  • Data - Controls whether the EMLoader.dll should be loaded using the legacy AppInit_DLLs value instead of the driver. If this value is set to a non-zero value, the Environment Manager service will modify the AppInit_DLLs entry on start-up to include AsVfxLdrAppInit.dll; on stop it will also remove the entry. The AsVfxLdrAppInit.dll uses the same registry keys as the driver and loads the EMLoader.dll in a similar way to the driver.

This means that AsVfxLdrAppInit.dll appears in the AppInit_DLLs entry rather than EMLoader.dll as in previous releases.

The Applnit_DLLs must not be manually edited.