Solving Agent Unreachable issues in Horizon View 5.2 with Mixed Security Mode

I encountered an interesting failure message while performing an upgrade from VMware View 5.0 to Horizon View 5.2. In this case, some desktops in an automated pool running the 5.0 View Agent began showing “Agent Unreachable” after upgrading the Connection Servers to 5.2. The 5.0 View Agent is supported in a 5.2 environment during the upgrade process, which was required due to the vast amount of persistent desktops that needed agent updates.


Digging deeper into the logs, I found a few culprits:

  • Repeated entries in the VDM log showing “wsnm_jms died, restarting in a minute”
  • The wsnm log showed that the wsnm_jms process continued to restart endlessly

In the end, I referenced KB 2038679 entitled After reinstalling or upgrading the View 5.1.x agent, the View Administrator console reports the message: Agent UnreachableIt specifically calls out this issue with a 5.1 View Agent environment, but seems that a 5.0 View Agent environment is equally affected.

VMware explains the cause as being an agent upgrade or reinstall:

When the View Agent is reinstalled or upgraded, it may change the keypair used to identify the View Agent with the Connection Server. This issue occurs if the process of changing the key in the Connection Server configuration fails and, therefore, causes the communication between the View Agent and Connection Server to break. (source)

In my case, the 5.0 View Agent had been previously reinstalled on the desktops showing the issue.

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Since the older agent is only supported during the upgrade, it is best to quickly update all of the desktop View agents as soon as possible.


The suggested resolution in the KB for automated pools worked like a charm. The desktops running the older 5.0 View agent immediately transitioned from Agent Unreachable to Available. This gives you some more breathing room to get your agents updated to 5.2.

  1. In the View Administrator console, on the left pane to go View Configuration > Global Settings.
  2. Under Security, click Edit.
  3. Select Mixed or Disabled in the Message security mode dropdown. (I chose Mixed).

It is probably best to change this back to Enabled once the older agents updated to 5.2.