The error message below appears in Internet Explorer and Firefox when attempting to log into after upgrading from the ICA client to the XenApp client:

The instructions below detail how to resolve the error message in Internet Explorer and Mozilla Firefox on Windows but the Firefox instructions are also applicable on Mac OS X.


Internet Explorer

  1. Open Internet Explorer
  2. Go to Tools – Internet options

  3. Move to the Programs tab and select the Manage add-ons button
  4. Locate the Citrix ICA Client plugin and press Disable

  5. Press the Close button and then the OK button.
  6. Close Internet Explorer and re-open.
  7. Logon to
  8. Open the application

Please note that disabling the Citrix Plugin for Internet Explorer will cause problems accessing



Mozilla Firefox

  1. Open Mozilla Firefox
  2. Open the Add-ons

  3. Select Plugins, and then Set Citrix ICA Client xx.x… to never activate

  4. Close and re-open Mozilla Firefox and try to logon again. Try to launch the application again.