Maintenance mode prevents users from accessing their desktops. If you start machines in maintenance mode, Horizon 7 places each machine in maintenance mode when the machine is created.
In a dedicated-assignment pool, you can use maintenance mode to log in to a machine without having to reassign ownership to your own administrator account. When you finish the customization, you do not have to return ownership to the user assigned to the machine.
In a floating-assignment pool, you can test machines in maintenance mode before you let users log in.
To perform the same customization on all machines in an automated pool, customize the virtual machine you prepare as a template or parent. View deploys your customization to all the machines. When you create the pool, you can also use a Sysprep customization specification to configure all the machines with licensing, domain attachment, DHCP settings, and other computer properties.
You can start machines in maintenance mode if you manually specify machine names for the pool, not if you name machines by providing a naming pattern.