P1 formatted emails are only seen in the Exchange Journal mailbox and are the wrapper for the P2 emails. P1 format includes the BCC and DL recipients.
P2 formatted emails are what a user would see when viewing from Outlook.
Figure 1: The original message as created

P2 mail format is the format that is seen when viewed in Outlook. The individual members of any Distribution List (DL) are not displayed as well as the BCC field recipients are not displayed (see Figure 2).
Figure 2: P2 mail format

P1 mail format is the format for the Exchange Journal mailbox. P1 is a wrapper around the P2 message. The P1 wrapper contains the individuals from any DL list as well as BCC recipients (see Figure 3 in red). The original P2 message is an attachment of a P1 message (see Figure 3 in green).
Figure 3: P1 mail format

Microsoft Exchange 2010+ modified how mail is distributed when the recipient list exceeds 1,000 members. When the recipient list exceeds 1,000 members the message is duplicated, and the recipient list is broken into 1,000 different recipients per message. This parsing of the recipient list assists in accelerating the time to deliver messages to large groups of people (aka: load balancing).
An example of load balancing would be a company-wide email with a list of 4,000 employees. The Exchange environment will make four copies of the message and attach a different set of 1,000 recipients to each copy. These copies to are sent to different email servers to load balance the delivery of the 4,000 emails.
Collecting from a user’s mailbox will be in the P2 format. Collecting directly from the Exchange Journal mailbox will be in the P1 format.
EV will archive the P2 format for emails retrieved from individual user mailboxes.
As for P1 (Journal mailbox) ingestion, EV will receive a message from the Exchange Journal mailbox and start a five-minute timer for that message. The five-minute timer allows duplicate ‘copies’ of the message to also be received by EV. In the previous example of 4,000 recipients, there would be four copies of the message. Once the five-minute time has elapsed, EV will store one copy of the message (aka: Single Instance Storage SIS) and index all 4,000 members of the distribution list.
EV version 10.0.2 introduced the P1 extraction method. The P1 extraction method allows eDiscovery products to extract all copies of a Journal message. The P1 extraction method also allows the calling product to obtain the complete list of recipients and not be restricted to the first 1,000 recipients in the TO and CC fields.
eDiscovery Platform (eDP/Clearwell) was the first product to take advantage of the new P1 extraction method. eDP receives each copy of the Journal message and stitches the headers from each message together while saving one copy of the message with a complete list of recipients from distribution lists and BCC recipients.
Discovery Accelerator will export the Journal email in the P2 format and will contain the BCC:

eDP will collect the Journal email in the P1 format that will contain the BCC as well as expand the Distribution Lists:

eDP processes and exports messages in different formats depending on settings the user makes.
Processing > Settings
Each case can select to process the Journal envelope information or exclude the information:

Export > Metadata > Options



The results of each style of message and settings will be discussed separately below.
A. P1 email with ‘Process journal envelope information’ enabled
B. P1 email with ‘Process journal envelope information’ NOT enabled
C. P2 email, the ‘Process journal envelope information’ has no effect on the P2 formatted email messages
- Text View

- Native View

- PDF Print

- Export (Metadata: In original journal format)

- Export (Metadata: By merging recipient lists)
By merging the recipient list, the message will display in P2 format with the expanded recipient list

- Export (Metadata: Messages in HTML format)

- Export (Native Only)

- Text View

The actual message displayed as an attachment

- Native View


- PDF Print


- Export (Metadata: In original journal format)
- Export (Metadata: By merging recipient lists)
- Export (Metadata: Messages in HTML format)

- Export (Native Only)

- Text View

- Native View

- PDF Print

- Export (Metadata: In original journal format)

- Export (Metadata: By merging recipient lists)

- Export (Metadata: Messages in HTML format)
- Export (Native Only)
