Below is a practitioner‑level explanation of how SharePoint and Teams site types, channels, and UI constructs map to actual data locations from the perspective of a Microsoft Purview eDiscovery user whose job is to correctly identify legal hold and collection targets. This is grounded in Microsoft documentation and eDiscovery‑focused guidance, with emphasis on where data truly lives vs. how users see it.

Sources: [learn.microsoft.com], [ediscovery…ournal.com], [m365admin….sontek.net], [petri.com], [microsoft.github.io], [automatedi…utions.com]

The Core Principle for eDiscovery Users

The Microsoft 365 UI is an abstraction layer.
Purview eDiscovery operates on the underlying workloads: SharePoint sites, OneDrive sites, Exchange mailboxes, and group mailboxes.

Understanding what the UI represents versus what must be placed on hold or collected is the difference between a defensible collection and a silent gap.

1. SharePoint Site Types (What You Can Actually Hold)

1.1 Team Sites (Microsoft 365 Group–Connected)

How users see it

• A Team in Microsoft Teams
• A SharePoint “Team site”
• Often surfaced as “Files” in a Team

What it really is

• A SharePoint site collection connected to:
  • A Microsoft 365 Group
  • An Exchange group mailbox
  • A Planner plan, etc.

eDiscovery implications

• Files live in a single default document library
• Each standard channel is just a folder in that library
• Holding the site URL preserves all standard channel files

Correct hold target template

SharePoint site: https://tenant.sharepoint.com/sites/<TeamName>

1.2 Communication Sites

How users see it

• Intranet or publishing‑style sites
• Often read‑only for most users

What it really is

• A standalone SharePoint site
• No M365 Group, no Teams backing

eDiscovery implications

• Treated exactly like any other SharePoint site
• Fewer collaboration artifacts, mostly documents and pages

Correct hold target template

SharePoint site: https://tenant.sharepoint.com/sites/<CommSite>

1.3 OneDrive for Business Sites

How users see it

• “My files”
• Files shared in 1:1 or group chats

What it really is

• A personal SharePoint site per user

eDiscovery implications

• Required for:
  • Files shared in 1-1 Teams chats
  • Drafts never uploaded to a Team
• Often overlooked if Teams is the entry point

Correct hold target

OneDrive account for custodian selected from Source UI OR https://edjgroupinc-my.sharepoint.com/personal/<UserID>/

2. Document Libraries (UI vs Reality)

2.1 Libraries Are Not Sites

UI confusion

• Users think “library” = container you can target

Reality

• eDiscovery cannot hold a library directly
• You must hold the entire site, then scope via query

Correct approach

• Hold the site
• Filter during collection using Path: queries

2.2 Folders Are Just Paths

UI

• Channels, folders, shortcuts, synced views

Reality

• Everything resolves to a URL path

eDiscovery‑relevant filter

DocumentLink:”/Shared Documents/Channel Name”

3. Microsoft Teams: The Most Common Source of Mistakes

3.1 Standard Channels

UI

• Visible to all team members
• “Files” tab per channel

Reality

• Folder inside the parent Team site’s document library

eDiscovery

• Holding the Team site covers all standard channels
• Chat messages live in the group mailbox, not SharePoint

Targets

• SharePoint Team site (files)
• M365 Group mailbox (messages)

3.2 Private Channels (High‑Risk for Misses)

UI

• Looks like just another channel
• Separate permissions

Reality

• Separate SharePoint site collection
• Files do NOT live in the parent Team site
• Chat messages stored in Parent site mailbox, not a separate channel mailbox as of late 2025 testing. This may change, so always validate in your tenant.

Required eDiscovery targets

• You must add Private channel SharePoint site as a separate target
• Recommend adding mailboxes of each private channel member

Common failure

Holding only the Team site does nothing for private channel files.

3.3 Shared Channels

UI

• Appears inside a Team
• Can include external users

Reality

• Separate SharePoint site created for the channel
• System mailbox stores messages

Required targets

• Shared channel SharePoint site
• Associated channel mailbox (handled automatically in Premium)

4. How Purview eDiscovery Abstracts This (Standard vs Premium)

4.1 eDiscovery Standard

• You must manually identify:
  • SharePoint sites
  • OneDrive accounts
  • Mailboxes
• Teams is not a first‑class object

Risk

• Easy to miss private/shared channel sites

4.2 eDiscovery Premium

• Teams and channels can be added as non‑custodial data sources
• Purview resolves:
  • Associated SharePoint sites
  • Mailboxes automatically

Best practice

• Use Teams channel targeting when available
• Still validate resolved sites before relying on it

5. UI Constructs That Mislead eDiscovery Scoping

6. Mental Model for Defensible Targeting

Always translate UI → Workload → Location

1. Where does the file actually live?
2. Is it a site, mailbox, or OneDrive?
3. Is the channel standard, private, or shared?
4. What additional site was silently created?

If you answer those four, you will not miss data.