Powershell: looping through list of names from exchange query

Question

My Goal is to apply a retention policy to newly created mailboxes. Details from previous article here.

My Current Script code is located here for easy readability or below:

# Get Start Time for script timer
$startDTM = (Get-Date)

#Authenticate using cached credentials or re-prompt for credentials.
if (Test-Path C:\temp\mycred.xml) {
    $UserCredential = Import-CliXML C:\temp\mycred.xml}
else{
    Get-Credential | Export-CliXml C:\temp\mycred.xml
    $UserCredential = Import-CliXML C:\temp\mycred.xml}

#Connect to Exchange Server
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri http://munprdcasht04.exchange.com/PowerShell/ -Authentication Kerberos -Credential $UserCredential
    Import-PSSession $Session

#returns alias' for mailboxes where creation date is <= 7 days and
#resides on "ABC" or "DEF" server and has no retention policy applied
$NeedsRetentions = (Get-Mailbox -ResultSize Unlimited| Where-Object {
    ($_.WhenCreated –ge ((Get-Date).Adddays(-7))) -and
    (($_.ServerName -like "*munprdmbxa*") -or ($_.ServerName -like "*wauprdexa*")) -and
    ($_.retentionpolicy -ne "PurgeDeletedItemsFolder_60days")} |
    ft -auto alias)  

ForEach ($NeedsRetention in $NeedsRetentions){
    set-mailbox -Identity $NeedsRetention -RetentionPolicy "PurgeDeletedItemsFolder_60days"
    }

# Get End Time
$endDTM = (Get-Date)

# Echo Time elapsed
"Elapsed Time: $(($endDTM-$startDTM).totalseconds) seconds"

When I echo the $NeedsRetentions i receive the list of AD users that i need to apply a retention policy to. But for some reason, when i loop through the the variable list with the below loop it errors out saying that the -Identity is no valid.

ForEach ($NeedsRetention in $NeedsRetentions){
    set-mailbox -Identity $NeedsRetention -RetentionPolicy "PurgeDeletedItemsFolder_60days"
    }

To troubleshoot i reduced the loop to this in order to display the individual usernames being affected by the script:

ForEach ($NeedsRetention in $NeedsRetentions){
[System.Windows.Forms.MessageBox]::Show($NeedsRetention)
}

Doing this causes a message box to show up for every line in the variable but the string seems to be empty and thus the default message shows up on the message box.

Any ideas why $NeedsRetention isn't passing correctly into my loop task?

Answer 1

The problem is that you saved the result from a Format-*-cmdlet (in this case Format-Table by using the alias ft).

Never save the results from Format-* cmdlets to a variable. Format-*-cmdlets are for GUI/visual presentation only and turns your useful mailbox-objects into special format-objects that are useless for anything else then console-/file-output.

Modify:

$NeedsRetentions = (Get-Mailbox -ResultSize Unlimited| Where-Object {
    ($_.WhenCreated –ge ((Get-Date).Adddays(-7))) -and
    (($_.ServerName -like "*munprdmbxa*") -or ($_.ServerName -like "*wauprdexa*")) -and
    ($_.retentionpolicy -ne "PurgeDeletedItemsFolder_60days")} |
    ft -auto alias) 

To:

$NeedsRetentions = Get-Mailbox -ResultSize Unlimited| Where-Object {
    ($_.WhenCreated –ge ((Get-Date).Adddays(-7))) -and
    (($_.ServerName -like "*munprdmbxa*") -or ($_.ServerName -like "*wauprdexa*")) -and
    ($_.retentionpolicy -ne "PurgeDeletedItemsFolder_60days")}

If you want to output the $NeedsRetentions-objects to the console before continuing with modifying the mailboxes, then do that as a separate command (without saving the format-output). Ex:

$NeedsRetentions | Format-Table -AutoSize