KBI 312110 Issue Addressed: VMware Runtime Error: You Have Modified The Global:DefaultVIServer and Global:DefaultVIServers System Variables


Argent Omega 2.2A-2307-B and earlier


Friday, 13 October 2023


When running Connectivity Rule and VMware Rules against VMware objects, such as ESX host, Virtual Machines, Datacenter, etc., Rules can randomly fail. Following lines can be found in ArgentOmegaExecutor*_Log.txt:

Runtime Error: You have modified the global:DefaultVIServer and global:DefaultVIServers system variables. This is not allowed. Please reset them to $null and reconnect to the vSphere server.

The issue has been addressed in Argent Omega 2.2A-2310-A.

Technical Background

Argent Omega uses PowerCLI to monitor VMware objects. Before using any function, connection must be established with vCenter or ESX host. The connection is very CPU intensive and resource costing. To minimize resource usage, the connection is pooled and re-used.

However, it is found that PowerCLI is not thread-safe in recent version 6.x. As result, the above runtime error happens randomly.

Argent Omega addresses this issue by limiting to single shared connection for each Executor process and use multiple Executor processes to achieve performance by parallelism.


Upgrade to Argent Omega 2.2A-2310-A or later.

For users who cannot upgrade immediately, use the option ‘Spawn New Task Executor Process’ in Relator running VMware Rules.

Note: This option could have performance hit on Argent Omega Generator.

For further assistance, please contact Argent on Instant Help at