ESXi 6.5.0 fails to start a VM with a message "Maximum virtual machines limit reached: ## (#### worlds)"

Maximum virtual machines limit reached: ## (##### worlds)

ESXi 6.5.0 by default determines the maximum number of VMs dynamically at runtime. In certain scenarios this might be too conservative and you will not be able to start a virtual machine. If you are observing a message like below when starting a VM then you have hit the limit.

Maximum virtual machines limit reached: ## (##### worlds).

This behavior is controlled by VMkernel.Boot.maxVMs in Advanced settings. Change this to a value that might be reasonable based on CPU, memory and network capacity. The same setting can be changed from SSH shell like below:

[root@localhost:~] esxcli system settings kernel set -s maxVMs -v 1024

Reboot the server for this change to take effect.
Tag: ESXi