You can’t update a mailbox if double-coded characters are included in Exchange Server 2016

Symptoms

Consider the following scenario:

• You have a Microsoft Exchange Server 2016 environment or a mixed environment that has Exchange Server 2013 and Exchange Server 2016.

• Cumulative Update 5 is installed on Exchange Server 2016.

• You have an email address policy that generates the first name or last name (%g, %s) as the primary email address for mailboxes. Your email address policy may be like this:
  
  %rÅa%råa%rÄa%räa%rÖo%röo%g.%rÅa%råa%rÄa%räa%rÖo%röo%rÜU%rüu%s@contoso.com

• In the Exchange environment, a user object has one of the following umlaut characters in the first or last name: 
  
  ü, Ü, Ö, ö, Ä, ä, Å, å, ß, ÿ

In this scenario, you encounter the following issues:

• You receive the following error message when you try to update a mailbox by using the Enable-Mailbox or Set-Mailbox command:
  
  Processing data for a remote command failed with the following error message: [ClientAccessServer=ServerName,BackEndServ
  er=ServerName.contoso.com,RequestId=RequestId,TimeStamp=DateTime] [FailureCategory
  =WSMan-Others] For more information, see the about_Remote_Troubleshooting Help topic.
      + CategoryInfo          : OperationStopped: (ServerName.contoso.com:String) [], PSRemotingTransportException
      + FullyQualifiedErrorId : JobFailure
      + PSComputerName        : ServerName.contoso.com
  
  Unhandled Exception: System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

• You receive the follolwing error message when you try to update a mailbox in Exchange Admin Center:
  
  The address 'SMTP:ÿmer@contoso.com' is invalid: Specified argument was out of the range of valid values. Parameter name: The address 'ÿmer@contoso.com' is not a valid SMTP address.

Resolution

To resolve this issue, install Cumulative Update 6 for Exchange Server 2016.