Administrators have the ability to set plain text or HTML as the default format in the Notes field in Calendar items. The ability to change the format of the Notes field was added in an update, with the default format set to HTML, but the default can be changed to Plain Text, RTF, or HTML by editing the registry.
This will not affect the ability to change the format in any appointment or meeting, it only sets the default format for new Calendar items.
- Open the registry editor and browse to HKEY_CURRENT_USER\SOFTWARE\Microsoft\Office\16.0\Outlook\Options\Calendar
- Right-click on the calendar key and choose New > DWORD.
- Type or paste CalendarEditorPreference as the DWORD name then press Enter.
- Right-click on CalendarEditorPreference, and choose Modify.
- In the Value data box, type one of the following values (as Hexadecimal) and click OK.
10000 for Plain Text format
20000 for HTML format
30000 for Rich Text format
- Close the registry editor and restart Outlook for the setting to take effect.
If you don't want to edit the registry yourself, download and run this .reg file: CalendarEditorPreference