Why do I get the message Display Protocol for this desktop is currently busy processing a request

Scenario

Re-connecting to a VMware Horizon View virtual desktop takes a long time and the message "The display protocol for this desktop is currently busy processing a request. Please contact your system administrator" is displayed.

The message was displayed alternating with a "The View Connection Server is preparing your desktop message" for many minutes.  Once connected a black screen was displayed with the PCoIP Zero Client displaying a "preparing desktop" message for another minute or so.  Note the PCoIP Zero Client Enable Preparing Desktop Overlay was set.  The desktop took some time to display all of the desktop windows. 

PCoIP Zero Client log entries indicate the connection query delay and connection retry

2015-05-30T13:27:32Z> LVL:2 RC:   2        MGMT_VDM :The display protocol for this desktop is currently busy processing a request. Please contact y
2015-05-30T13:27:35Z> LVL:3 RC:   0        MGMT_VDM :DESKTOPS.VCS_QUERY_CONNECTION: Transition 71 into DESKTOPS.VCS_QUERY_DELAY
2015-05-30T13:27:37Z> LVL:3 RC:   0        MGMT_VDM :DESKTOPS.VCS_QUERY_DELAY: Transition 137 into DESKTOPS.VCS_QUERY_CONNECTION

Cause

This message can be displayed when the virtual desktop is busy processing a VMware Connection Server request which prevents/delays the connection completion. 

Example 1:

Scenario

• In the scenario above the desktop had heavy loading of 95%-100% CPU loading on multiple cores, high memory utilization due to a desktop search engine indexing application. The desktop search tool indexing performance was set to "unrestricted (use all computer resources)".

Workaround

• For this scenario, the workaround was to either set the application to limit search indexing performance to "Limited" or "Paused" 

Resolution

Contact VMware to determine the root cause.