There are two possible solutions to this issue.Solution 1
This issue is only seen when the 'DontConvertBodyFromRTF' registry setting is used.
The 'DontConvertBodyFromRTF' registry setting was introduced to remove Legacy Conversion processes that were seen to introduce high CPU levels on the Exchange server.
For more information on the 'DontConvertBodyFromRTF' registry setting please refer to the following URL:Large numbers of RPC requests and high levels of CPU usage on Exchange servers running Data Protection
If you are not experiencing High CPU issues we recommend that the 'DontConvertBodyFromRTF' setting is disabled (DontConvertBodyFromRTF = 0). When the setting is disabled the Data Protection code retrieves the text from the RTF message body MAPI property which renders the results correctly.Solution 2FIX:SO05903
(incorporating Integration_x64_15.20_HF0192) has been released to programmatically address this issue. When the Exchange nodes set the option of 'DontConvertBodyFromRTF' registry setting to 1, the non-English characters in plain text format message are rendered as '?' by the MAPI library in the iConsole.
This hotfix resolves the rendering issue and displays the message body in Rich Text format in the iConsole instead of plain text format.