How to fix #{DisplayName=Firstname Lastname} - powershell

Question

#{DisplayName=Firstname Lastname} needs to be just 'Firstname Lastname' because get-mailbox -identity '#{DisplayName=Firstname Lastname} won't work.
I've tried using the -replace cmdlet to remove text.
$Olduser = Get-MsolUser -all | Where-Object {$_.BlockCredential -eq $True -and $_.isLicensed -eq $false} | Select-Object displayName,userPrincipalName,BlockCredential,isLicensed
$OldUser | fl *
Using the -replace, I expected that the output will be without '#{DisplayName}'
Cannot process argument transformation on parameter 'Identity'. Cannot convert value "#{DisplayName=X X}" to type "Microsoft.Exchange.Configuration.Tasks.MailboxIdParameter". Error: "Cannot conve
rt the "#{DisplayName=X X}" value of type "Deserialized.Selected.Microsoft.Online.Administration.User" to type "Microsoft.Exchange.Configuration.Tasks.MailboxIdParameter"."
+ CategoryInfo : InvalidData: (:) [Get-Mailbox], ParameterBindin...mationException
+ FullyQualifiedErrorId : ParameterArgumentTransformationError,Get-Mailbox
+ PSComputerName : outlook.office365.com

Answer 1

You are passing an object type with properties to a parameter (-Identity) that expects just a value. As a result, PowerShell converts that object into a string, which results in the value #{DisplayName=Firstname Lastname}. If you access the DisplayName property before passing it into the -Identity parameter, your issue will be resolved.
Get-Mailbox -Identity $OldUser.DisplayName
# Or
$OldUser.DisplayName | Get-Mailbox
You can replicate a similar behavior by typing the following at the console:
[string]$OldUser