Add users to SP Group

Question

I am using following PS script to add users from a text file. Some of the users in the text file are inactive or gone (basically can't be resolved). The error message from the catch block is executed for all the users. If invalid user then it should display $spUser does not exists. Can anyone see what am I doing incorrect here? Just wanted to mention that valid AD users are getting added. EnsureUser is throwing exception when user not found in AD.

$webUrl = "http://server"
$web = Get-SPWeb $webUrl
$fileWithPath = "N:\Staging\Users.txt"
$content = Get-Content $fileWithPath
$spGroup = "Northwest Region Sales"
$rd="Read"

foreach($user in $content)
{    
    try
    {
        $spUser = $web.EnsureUser($user)
        if($spUser -ne $null)
        {
        Write-Host $spuser
            Write-Host "Adding " $spUser
            $web.SiteGroups[$spGroup].AddUser($spUser)
            Write-Host $user  " User added to the group successfully"
        }
        else
        {
        Write-Host $spUser " does not exists"
    }
    }
    catch
    {
        Write-Host "Error occured on " $user
    } 
}

Answer 1

To summarize comments.

SpWeb.EnsureUser method will throw an exception if user account doesn't exist in Active Directory or if it is disabled.

Code provided in question could look like this (in foreach loop):

try
{
    $spUser = $web.EnsureUser($user)

    Write-Host "Adding " $spUser
    $web.SiteGroups[$spGroup].AddUser($spUser)
    Write-Host $user  " User added to the group successfully"
}
catch
{
    Write-Host $spUser " does not exists"
} 

Using try catch block is not the best option but in this case it is the only option.

Some more details with C# example on how to check AD for user can be found here:

• Checking if a User Account is Enabled in Active Directory