Customize Saving Email Headers in SharePoint and Teams Columns Using harmon.ie Classic

Before you begin, we recommend reading Automatically Save Email Headers in SharePoint and Teams Columns Using harmon.ie Classic, which explains the simpler, automatic configuration method.

This article walks you through how to customize the mapping of email headers to SharePoint or Teams columns using the SharePoint web interface. This method requires Microsoft 365 admin assistance.

Steps to Customize Email Header Mapping

1. Add email columns to SharePoint or Teams

Below you can find the full list of email columns. Define the metadata columns you want to use in your Microsoft 365 site or library. You don’t need to include all of them – just those that support your users’ search and organization needs. Recommended columns are marked with an asterisk (*).

MailPreviewData is a harmon.ie-specific field that enables previewing email messages. We recommend adding it.
ConversationTopic allows you to group emails by thread – another recommended column.

2. Use Default or Custom Column Names

If you use harmon.ie’s default column names (as appear in the email header table below), harmon.ie automatically maps email headers to those fields.

If you need custom column names, define the mapping by provisioning the MailHeaderMappingList key.

[Download reg key sample]

3. (Recommended) Create a Custom Email Content Type

Create a dedicated email content type that includes the email columns from Step 1. Add it to your target document libraries.

If the content type is named “E-mail” or “Email”, harmon.ie will automatically apply it to uploaded emails.
To use a different name, follow the steps in How to Configure Mail Content Types for Emails Uploaded to SharePoint via harmon.ie Classic.
We recommend hiding this content type from the New button in SharePoint.

4. (Optional) Create an “Email View”

Create a SharePoint view with the email columns to give users an inbox-style experience when viewing saved messages.

Supported email header columns

Email Column	Type	Description
Bcc	Single line of text	Blind copy recipients. Only saved if explicitly enabled by an administrator
Categories	Multiple lines of text	Message categories
Cc*	Single line of text	Carbon copy recipients
ConversationIndex	Single line of text	Unique conversation identifier
ConversationTopic*	Single line of text	A harmon.ie-specofic column used for grouping emails
Date*	Date and Time	Sent time
From*	Single line of text	Sender’s address
HasAttachments*	Yes/No or Single line of text	Indicates if the message has attachments. The default value should be “No”
Importance	Single line of text	Email importance level
InReplyTo	Single line of text	Previous correspondence that this message replies to
MailPreviewData*	Multiple lines of text	A harmon.ie-specific column that enables previewing email messages in harmon.ie
MessageID	Single line of text	Unique message ID
MessageClass	Single line of text	Outlook item type (message, appointment, post, etc.). Used to show the correct item icon. Read How to Assign Custom Icons to Outlook Items Uploaded via harmon.ie Classic to learn more
Received	Date and Time	Received date and time
References	Single line of text	Related message identifiers
ReplyTo	Single line of text	Reply-to address(s)
Subject*	Single line of text	Email subject line
Sensitivity	Single line of text	Sensitivity level
To*	Single line of text	Primary recipients

All multiple line properties should be defined as plain text.

Grouping email messages

harmon.ie uses the ConversationTopic column in SharePoint to group related emails into a conversation view. harmon.ie automatically strips prefixes like “RE:” and “FW:” from the subject and saves the cleaned-up version in this column.

This feature allows you to view email messages in a pseudo-conversation view.

Saving Bcc recipients

To save the list of Bcc recipients as metadata, provision the ExposeBcc registry key to all users, and set its value to True.

[Download reg key sample]

Troubleshooting: Non-English Characters

Issue: Non-English characters in email headers are not saved correctly to SharePoint.

Cause: Outlook is configured to save messages in ANSI format instead of Unicode format which holds support for international characters.

Resolution: Configure Outlook to save messages in Unicode format:

In Outlook: Open the Options dialog, click Mail and check Use Unicode Format under the Save messages.
In Group Policy: enable Use Unicode format when dragging email message to file system.