Information
This policy setting controls whether e-mail messages dragged from Outlook to the file system are saved in Unicode or ANSI format.
The recommended state for this setting is: Disabled.
Rationale:
Unicode text is vulnerable to homograph attacks, in which characters are replaced by different but similar-looking characters. For example, the Cyrillic letter ? (U+0430) appears identical to the Latin letter a (U+0061) in many typefaces, but is actually a different character. Homographs can be used in 'phishing' attacks to convince victims to visit fraudulent Web sites and enter sensitive information.
Impact:
ANSI file encoding may limit the overall size a .msg file can reach, although a single mail item should not be of concern.
Solution
To establish the recommended configuration via GP, set the following UI path to Disabled:
User Configuration\Administrative Templates\Microsoft Outlook 2016\Outlook Options\Other\Advanced\Use Unicode format when dragging e-mail message to file system
Default Value:
Enabled. (Outlook uses Unicode character encoding.)