Get-Recipient intermittently exhibit high latency, partial result sets, or timeout exceptions.

Hi Wortles Aslanbekov

Based on my research, this behavior stems from two resource ceilings beneath the Exchange layer.

• First, the WinRM shell quota limits memory allocated per remote shell when breached by large result sets, the pipeline truncates silently with no explicit error.
• Second, Exchange's throttling policy caps PowerShellMaxConcurrency and ExchangeMaxCmdlets per connecting account once exhausted, cmdlets queue or return partial data without any visible throttling message.

Link reference: New-ThrottlingPolicy (ExchangePowerShell) | Microsoft Learn

In this situation, you can try the approaches below:

Step 1: Correct WinRM shell memory quota on each CAS/Mailbox server.

Behavior is unsupported if MaxMemoryPerShellMB is set below the default of 1024 MB. This document verify and correct on each server:

winrm get winrm/config/winrs 
winrm set winrm/config/winrs '@{MaxMemoryPerShellMB="1024"}' 
winrm set winrm/config/winrs '@{MaxConcurrentUsers="20"}' 
winrm set winrm/config/winrs '@{MaxShellsPerUser="15"}'

Step 2: Create a dedicated throttling policy for admin/automation accounts.

Microsoft recommends against modifying the default GlobalThrottlingPolicy as it may be overwritten by future Exchange updates. Create a custom policy instead.

New-ThrottlingPolicy -Name "EMS-Admin-Policy" `   
-PowerShellMaxConcurrency 20 `   
-PowerShellMaxRunspaces 25 `   
-ExchangeMaxCmdlets Unlimited `   
-IsServiceAccount
Set-ThrottlingPolicyAssociation -Identity "svc-exchangeadmin" `   
-ThrottlingPolicy "EMS-Admin-Policy"

Hope my answer will help you.

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