This article is designed to describe how to remove a machine from machine catalog as well as hypervisor through PowerShell command.
asnp Citrix*
Get-BrokerMachine -MachineName "domain\vmname" | Remove-BrokerMachine -Desktopgroup "delivery gorup name"
Get-provvm -ProvisioningSchemeName "provisioningSchemeName" | unlock-provvm
Get-Provvm -vmname "vmname" | Remove-provvm
Get-BrokerMachine "domain\vmname" | Remove-BrokerMachine
Get-AcctADAccount | select IdentityPoolName, ADAccountSid
Remove-AcctADAccount -ADAccountSid "ADAccountSID is from above step" -IdentityPoolName "Identitypoolname is from above step" -RemovalOption "delete"