Consider the following scenario:
You are running Microsoft Outlook in online mode in an Exchange Server 2016 or Office 365 environment.
The Preferred encoding for outgoing messages option in Outlook is set to Cyrillic KOI8-R (the default encoding setting for the Russian version of Outlook).
You create a message that contains some Russian characters, and then you save it as a draft.
In this scenario, the body of the message is garbled after you send this draft. You can see it usual only if you manually set the character set for this message to Cyrillic KOI8-R in Outlook.
This issue occurs because the Exchange server doesn't update the character set in the PR_BODY_HTML property when the server changes the character set in the PR_INTERNET_CPID property. Therefore, the message body is garbled when Outlook tries to display it.
Configure the Outlook client to use UTF-8 for the Preferred encoding for outgoing messages option. To do this, follow these steps:
In Outlook, select File > Option > Advanced.
In the International options section, set the Preferred encoding for outgoing messages option to UTF-8.
To fix this issue, install Cumulative Update 11 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
Before you do other settings, you should make sure that you specify the following Registry settings in Windows Registry Editor Version 5.00.
There's a performance effect if this registry key is used. So, it should be configured for use only in environments where the functionality is required.
a) Action: "Create"
b) Hive: "HKEY_LOCAL_MACHINE\"
c) Key path: SOFTWARE\Microsoft\ExchangeServer\v15\Storage\ContentConversion
d) Value name: AllowRestampCharsetOnInernetCPIDMismatch
e) Value type: REG_DWORD
f) Value data: 1
g) Base: Hexadecimal
In addition, you need to manually create the "Storage" key and its sub key "ContentConversion" if you can't find them under the key path.
For more information about content conversion, see Content conversion.
For more information about the PidTagBodyHtml canonical property, see PidTagBodyHtml canonical property.
For more information about message-encoding options, see Message-encoding options.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminology that Microsoft uses to describe software updates.