Error when installing Cumulative Update 19 for Exchange 2016

Question

Error: The following error was generated when "$error.Clear(); if (!$RoleIsDatacenter -and !$RoleIsDatacenterDedicated) { $arbMbxname = "SystemMailbox{1f05a927-" + [System.Guid]::NewGuid().ToString().Substring(9) + "}"; $arbMbxLastName = "MSExchApproval 1f05a927-3be2-4fb9-aa03-b59fe3b56f4c"; $arbUser = @(Get-User -Filter {LastName -eq $arbMbxLastName} -IgnoreDefaultScope -ResultSize 1); if ($arbUser.Length -eq 0) { $arbUser = @(Get-User -Arbitration -Filter {LastName -eq $arbMbxLastName} -IgnoreDefaultScope -ResultSize 1); } if ($arbUser.Length -eq 0) { Install-UserAccount -Name $arbMbxname -LastName $arbMbxLastName; } } " was run: "Microsoft.Exchange.Data.Directory.NameConversionException: Failed to convert name format for "Domain/Users", error 1722. at Microsoft.Exchange.Data.Directory.NativeHelpers.DistinguishedNameFromCanonicalName(String canonicalName, ADServerSettings serverSettings) at Microsoft.Exchange.Management.Deployment.InstallUserAccount.InternalValidate() at Microsoft.Exchange.Configuration.Tasks.Task.<ProcessRecord>b__91_1() at Microsoft.Exchange.Configuration.Tasks.Task.InvokeRetryableFunc(String funcName, Action func, Boolean terminatePipelineIfFailed)".

Answer 1

Hi @Labellep ,

From the error you shared, it seems that the issue is related to the arbitration Mailbox "MSExchApproval 1f05a927-3be2-4fb9-aa03-b59fe3b56f4c". Please try recreating this system mailbox and rerun the setup to check the result:
1.Open ADUC, remove the SystemMailbox{1f05a927-2390-47c4-81b3-55dc22299269} in CN=Users:

2.Run the following command from a Windows Command Prompt window:

<Virtual DVD drive letter>:\Setup.exe /IAcceptExchangeServerLicenseTerms /PrepareAD  

3.Run the following command in the Exchange Management Shell:

Get-User -ResultSize Unlimited | where {$_.Name -like "SystemMailbox{1f05a927*"} | Enable-Mailbox -Arbitration  

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