Check for Existing Computer in AD - powershell

Question

I'm trying to check for an existing computer name in AD before renaming the local computer. Below is the code that I started with, but don't know why it's failing.
When I enter a computer name (MNBLAP) that I know is in AD, it jumps down to the else statement. If I put in a computer name (RJKLAP) that I know doesn't exist, it throws an error.
$checkname = Get-ADComputer $newcomputername -ErrorAction SilentlyContinue
if ($checkname -eq $newcomputername){
Write-Host "The computer is already in AD."
}
else {
Write-Host "The computer is not in AD."
}
Any help would be greatly appreciated. Below is the error I receive
get-adcomputer : Cannot find an object with identity: 'RJKLAP' under: 'DC=domain,DC=domain'.
At C:\Scripts\CheckComputerName.ps1:25 char:14
+ ... checkname = get-adcomputer $newcomputername -ErrorAction SilentlyCont ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (RJKLAP:ADComputer) [Get-ADComputer], ADIdentityNotFoundException
+ FullyQualifiedErrorId : Cannot find an object with identity: 'RJKLAP' under: 'DC=domain,DC=domain'.,Microsoft.ActiveDirectory.Management.C
ommands.GetADComputer

Answer 1

The reason your if() statement fails is that Get-ADComputer returns an ADComputer object, not just the computer name.
To trap the error in case the machine name doesn't exist, use try/catch:
try{
$checkname = #(Get-ADComputer $newcomputername)
if($checkname.Count -eq 1){
# newcomputername found
Write-Host "The computer is already in AD."
}
}
catch [Microsoft.ActiveDirectory.Management.ADIdentityNotFoundException]{
# newcomputername not found
Write-Host "The computer is not in AD."
}