Esko Logo Back to Esko Support
Choose your language for a machine translation:


How to check the maximum Viewer sessions number and increase it? The operator gets the following message in Automation Engine Viewer:

Cannot read image parameters for filename.
Cannot retrieve image parameters because:

"You cannot view this file or get to the wanted zoom because you have reached the maximum number of allowed file streaming sessions".

Solve this problem by either

  • Choosing Reset file list and/or open Automation Engine Viewers.
  • Close the dialog box and/or open Automation Engine Viewers.
  • Ask your administrator to change the setting.


  1. In Automation Engine, you can check the current Viewer sessions number and the maximum concurrent Viewer sessions by going to this url (replace servername):
    For Automation Engine 20.0.0 and later: open a browser goto http://servername:18560/viewserver_client
    For Automation Engine versions prior to 20.0.0: open a browser and goto http://servername:8080/viewserver_client/
  2. Before increasing the amount, check the minimum system requirements page for your Automation Engine version: If the hardware is powerful, more sessions can be added but take into account that the Automation Engine's default limit for File Streaming Sessions is four. Increasing this number may lead to general slowness of the Automation Engine Server.
  3. If your system meets the minimum requirements to add / move viewing sessions, change it by doing the following:
    On Automation Engine 12.0.0 and later:
    1. Open the Server Admin webpage in your browser and log in as Administrator user.
    2. Go to Server Setup.
    3. Click the lock button to make changes.
    4. Increase the streaming session number in Processing Capabilities > Max. Sessions.
    On Automation Engine versions prior to 12.0.0:
    1. Go to the Server Admin tool by clicking Start > All Programs > Esko > Automation Engine 10.1 > Server Admin.
    2. Right-click Server Admin and select Run as Administrator.
    3. Click Servers > Manage Servers: Set System Password  Configure Server Task Capabilities > Next > Configure Task Capabilities.
    4. Change the Max. Sessions number as desired.

Please do not specify a very large number, because each extra session takes more resources. Increasing the streaming session number too high causes a general slowness of the Automation Engine Server.


Compare takes two View Sessions.

Article information
Applies toAutomation Engine 10 and higher versions
Last revised


AuthorJKO, HG, FL
CW Number162608