I get the following eror when trying to run Get-ClientAccessArray or New-ClientAccessArray [PS] C:\Windows\system32>Get-ClientAccessArray WARNING: An unexpected error has occurred and a Watson dump is being generated: An item with the same key has already been added. An item with the same key has already been added. + CategoryInfo : NotSpecified: (:) [Get-ClientAccessArray], ArgumentException + FullyQualifiedErrorId : System.ArgumentException,Microsoft.Exchange.Management.SystemConfigurationTasks.GetClientAccessArray Also the Exchange Service Host starts and then stop immediately Only error is that the server stopped unexpectedly

Please check if any MBX server or CAS server holds the multiple objects of the class “msExchProtocolCfgExchangeRPCService” in the following container, which will cause the same symptom CN=Protocols,CN=>Servername>,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=<Exchange Org>,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=<…>,DC=<…> The only object of the class “msExchProtocolCfgExchangeRPCService” in there should be “CN=RpcClientAccess” entry "Microsoft Exchange RPC Client Access" Service is hardcoded to look for an instance called "RpcClientAccess" and bound to its local server in the AD. If it finds one it is happy, if it doesn't, the symptom you have will appear Please take an AD backup, and then remove the entries other than “CN=RpcClientAccess”Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Any update?Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Hi, the procedure above resolve the same problem to me. Thanks. Guilherme Resende