Presentation Server 4.5 for Windows Server 2003,Presentation Server 4.5 for Windows Server 2003 x64 Edition,XenApp 5.0 for Windows Server 2003 x86,XenApp Plug-in for Windows (32/64 Bit)
Presentation Server 4.5 for Windows Server 2003,Presentation Server 4.5 for Windows Server 2003 x64 Edition,XenApp 5.0 for Windows Server 2003 x86,XenApp Plug-in for Windows (32/64 Bit)
This article provides information on troubleshooting ICA session performance.


Citrix Technical Support often receives inquiries regarding the performance or the responsiveness of sessions. This article assumes the ICA session has started and has not been disconnected.
CTX708444 – Configuring TCP KeepAlive Values to Improve WAN Links and ICA KeepAlives to Place ICA Session in a Disconnected State

There may be many reasons why ICA sessions are slow or unresponsive.


  1. Load balanced environments make it challenging to troubleshoot intermittent issues. Open the ICA Connection Center on the client machine and make a notation of the server. Notice Outlook is the only application within the session.

    User-added image

  2. Highlight the server. From the Properties tab determine if the incoming bytes and / or frames adjust themselves when performing an action within the application.

    User-added image

  3. If there is no noticeable “traffic,” Outlook appears hung. If there is noticeable “traffic,” Outlook may still be performing sluggish.

  4. Citrix Technical Support would ask that another application be launched within the same session, CTX159159 – Session Sharing Explained with Troubleshooting Steps and or on a different server. The results of this step will indicate whether the session is truly hung, (another application will not?? launch in the same session but launches on another server or the new application is also unresponsive within the same session) or whether the application itself is unresponsive (the second application is the session is responsive but the original application may be waiting on an internal request).

  5. If the session is unresponsive, are other sessions to the same server from different clients responsive? Is this a LAN/WAN issue? This will isolate the issue to a specific session or to the entire server. If the entire server’s ICA sessions are unresponsive, what happens if an RDP connection is attempted to the same problem server? If RDP is also unresponsive, are there any processes running on the server consuming high CPU, How to use the Userdump.exe tool to create a dump file, or using significant amount of memory? If an individual session is unresponsive, Citrix Technical Support may ask to use the SMC console.

  6. If the issue is isolated to an individual application process or it is determined that any session from a particular client is unresponsive, Citrix Technical Support may ask that the client side processes or the application process be dumped, How to use the Userdump.exe tool to create a dump file and sent to the appropriate parties for analysis.

  7. Can the session be shadowed? If so, does shadowing restore the expected behaviour?

  8. Generally, Network Traces do not?? help in situations where the session is already hung. If the entire session is sluggish, Network Traces may be used in tandem with the SMC Console output.

  9. Certain application may misbehave ONLY in a seamless session. Refer to CTX101644 – Seamless Configuration Settings and investigate the Citrix Knowledge Base for possible settings that could improve performance.

  10. Is the application highly graphical?

  11. Again, do earlier or later clients affect the behavior of the session(s)? The following statement from the 6.31 Client readme is to illustrate a possible scenario that has occurred. In depth troubleshooting, as previous outlined, is needed to make such determinations.If a user opened a new window or menu item repeatedly, the operating system's Graphical Device Interface (GDI) resources were reduced, and eventually, when GDI Resources were depleted, the operating system became unstable. GDI resource areas keep track of items that the operating system uses to draw graphics: pens, brushes, fonts, palettes, and so on. Each time a window is opened, it receives an allocation of GDI resources. When the window is closed, these GDI resources are released, freeing memory in the GDI resource area for other applications and windows. The ICA Client did not properly track the GDI brush resource and lost memory each time a new window was opened. The client now properly tracks the GDI brush resource, releasing its allocated memory when windows are closed.

  12. A previous server side fix stated: Creating many graphical device interface (GDI) objects (windows, fonts, bitmaps) depleted the hardcoded limit of the winstation paged pool. As a result, sessions froze on the server and could not be reset. The process that features the infinite thinwire loop went into a delay execute state.

  13. Do 16 or 256 colors sessions behave differently than High Color depth sessions?

  14. Does clearing compression or client bitmap cache improve performance?

  15. Does the issue happen in a pass-through session? CTX204071 - Screen Refresh Issues Through a Seamless Pass-Through Session.

Additional Resources

How to: Use Hot Keys to Capture a Crash Dump of a Process

How to Generate a Memory Dump File When a Server Stops Responding (Hangs)

Windows feature allows a Memory.dmp file to be generated with the keyboard

Qslice.exe: CPU Usage by Processes

Applicable Products


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