Exchange 2010 - Check if Mailbox Exists using C# and Remote PowerShell

The following is an example on how to use C# to check if exchange mailboxes exist in Exchange 2010 using remote PowerShell.

Imports, not all are used in the example function below:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.DirectoryServices;
using System.EnterpriseServices;
using System.Configuration;
using System.Security;
using System.Management.Automation;
using System.Management.Automation.Runspaces;
using System.Collections.ObjectModel;
using ActiveDs;
using System.Net;
using System.Security.Principal;
using System.Text.RegularExpressions;
using System.Security.Cryptography;
using System.Security.AccessControl;
/// <summary>
// Returns true or false if a mailbox is found to be associated with the given system (domain) account.
// </summary>
/// <param name="system">The domain of the account</param>
/// <param name="userid">The account name (samAccountName)</param>
/// <param name="exchangeRemoteServer">The URL for exchange powershell:</param>
/// <returns></returns>
public bool GetMailboxExists(string system, string userid, string exchangeRemoteServer)
 bool mailboxExists = false;
  // Assumes the process will run with proper priviledges to create mailboxes through powershell.
  WSManConnectionInfo connectionInfo = new WSManConnectionInfo(
   new Uri(exchangeRemoteServer),
   "", // This shouldn't change
    // Skip Certificate Verification
    connectionInfo.SkipCACheck = true;
    connectionInfo.SkipCNCheck = true;
    connectionInfo.SkipRevocationCheck = true;
    connectionInfo.AuthenticationMechanism = AuthenticationMechanism.NegotiateWithImplicitCredential;
  using (Runspace runspace = RunspaceFactory.CreateRunspace(connectionInfo))
   using (PowerShell powershell = PowerShell.Create())
    StringBuilder psScript = new StringBuilder("");
    psScript.AppendLine("Set-ADServerSettings -ViewEntireForest $true");
    psScript.AppendLine("[bool](Get-Mailbox -ErrorAction SilentlyContinue -Identity \"{0}\\{1}\" )");
    powershell.AddScript(string.Format(psScript.ToString(), system, userid));

    powershell.Runspace = runspace;

    Collection<PSObject> results = powershell.Invoke();
    if (results != null)
     if (results.Count > 0)
      mailboxExists = (bool)results[0].BaseObject;
      mailboxExists = false;
 catch (Exception ex)
  // Log your errors!
 return mailboxExists;
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