Export Microsoft 365 Mailboxes and Teams Data

Where Microsoft 365 keeps mail, chat and files

Exporting Microsoft 365 is easier once you know where each record sits. Teams messages are kept for compliance in Exchange Online mailboxes, and files shared in Teams are kept in OneDrive or SharePoint. Messages in 1:1 chats are stored in the Exchange Online mailbox of all chat participants, and all standard channel messages and posts are stored in the mailbox associated with the team. That is why a mailbox export can carry Teams history with it.

Source: Microsoft Learn: Finding content in Microsoft Teams in eDiscovery

How to export a Microsoft 365 mailbox with eDiscovery

eDiscovery in Microsoft Purview is the admin route for exporting mailboxes in bulk. When you export search results, you download mailbox items in PST files or as individual messages, and SharePoint and OneDrive content as copies of the documents. The person running it needs eDiscovery permissions and a license: assign the eDiscovery user a Microsoft 365 Enterprise E3 or E5 license, and a SharePoint E3 license to export SharePoint items reliably.

• Sign in to the Microsoft Purview portal with an account assigned eDiscovery permissions.
• Open the eDiscovery solution, select Cases, and create or open a case.
• On the Searches tab, create a search, add the mailboxes, sites and Teams you need as data sources, and run the query. Use date ranges to keep each export manageable.
• Select Export. Name the export and, for a tenant-wide search, choose whether to include departed users, guest users and shared Teams channels.
• Under messages, choose Organize conversation into HTML transcript and Include Teams and Viva Engage conversations if you want chat history in context.
• Under OneDrive and SharePoint items, choose how many document versions to export: latest, 10, 100 or all.
• Choose Export items with items report, then Create PSTs for messages, and start the export.
• Download from the Process manager page within 14 days. Exports that run more than seven days cancel automatically, so split very large ones.

Source: Microsoft Learn: Export search results in eDiscovery

Archive one Outlook mailbox to a PST file

For a single mailbox, classic Outlook can export to an Outlook Data File: File > Open & Export > Import/Export > Export to a file > Outlook Data File (.pst), select the account, keep Include subfolders ticked, and save. Only information for one account can be exported at a time, and new Outlook has its own export under Settings > Files > Export.

One default trips people up: by default, Outlook is set to download email for the past 1 year. Move the sync slider to All before exporting, or the archive will stop a year back. Do not save the PST to a OneDrive folder. For more than a handful of mailboxes, eDiscovery is faster and keeps the audit trail of what was exported.

Source: Microsoft Support: Export emails, contacts and calendar items to a .pst file

Microsoft Teams data export: chats, channels and meetings

Most companies export Teams through eDiscovery with HTML transcripts. Developers can use the Teams Export APIs in Microsoft Graph, which export 1:1, group, meeting and channel messages for a date range, with attachment information, reactions and links to meeting recordings and transcripts. To use them, organizations must have an active Microsoft Teams license assigned to the users whose data is being exported.

The APIs set the deadlines for deleted content. Messages a user deleted can be retrieved for up to 21 days. Deleted teams and channels can be captured for 30 days; after 30 days the teams and channels are hard deleted, and messages can't be retrieved. Deleted and inactive users' messages are reachable for 30 days.

Departed staff: the 30-day clock on mailboxes and OneDrive

When you delete a user, The employee's mailbox data is retained for 30 days after the account is removed, and after that it is permanently removed. If a hold or a Microsoft 365 retention policy is applied before the account is deleted, the mailbox becomes an inactive mailbox and is kept for the retention period. Microsoft's advice is blunt: if you want to keep the user's email, move it before you delete the account.

OneDrive follows its own rules. When a user is deleted, the delegate has 30 days by default to access and download the files they want to keep. OneDrive accounts without a valid license are archived on their 93rd unlicensed day, and after 12 months of unpaid archive the data might be deleted regardless of holds.

What happens to Microsoft 365 data after you cancel

For most business offers, a subscription that ends moves through Expired, Disabled and Deleted. Users keep access while Expired; only admins can reach the data while Disabled; then it is deleted. If you cancel within the cancellation window, the subscription moves directly to Disabled, and Any customer data that you leave behind might be deleted after 90 days and will be deleted no later than 180 days after cancellation.

Two exceptions matter. As of February 9, 2026, the Expired state no longer applies to license-based subscriptions bought directly through a Microsoft Customer Agreement. And if you explicitly delete a subscription, SharePoint and OneDrive content is deleted immediately. Enterprise and volume licensing customers have different periods; check your agreement.

Source: Microsoft Learn: What happens to my data when my Microsoft 365 for business subscription ends?

Keep mail, chat and documents linked

A good Microsoft 365 export lets someone follow a decision from the Teams thread to the email to the document version that was signed. These settings keep those links.

• Export with the items report; it lists every item with its source location and metadata.
• Include cloud attachments, so files linked in emails and chats come with the message.
• Export document versions, not only the latest, for contracts and plans that changed.
• Use HTML transcripts with the 12-hour context window for Teams, so a matching message keeps its conversation.
• Save the audit log while it exists. Standard audit records are retained for 180 days by default (Microsoft), longer only with E5-level licensing.
• Record the search query, date range and data sources of each export in a short note kept with the files.

Why years of email and Teams history matter now

Workplace email and chat are among the records buyers ask for. In 2026 a bankrupt airline's dataset, which included about 100 million emails and 500 million Microsoft Teams chats according to Axios, drew a $10 million winning bid. The data was to be deidentified, and the buyer agreed not to attempt to re-identify the users.

In Microsoft 365 the signal is in Teams channel threads where work is coordinated, in the email that carries approvals and customer commitments, and in SharePoint document versions that show how a contract or plan changed before it was signed. Those three only make sense together, which is why the export settings above keep conversations, cloud attachments and versions. A complete, linked tenant export is the starting point. See selling Slack, Teams and email archives, what company data is worth and what records can be sold.

Employee and customer privacy in a Microsoft 365 export

The tenant is the company's, but mailboxes and chats hold employees' personal messages and customers' details. Treat exports as sensitive: encrypt them, log who opens them, and check employee notices and works council or union agreements before anyone reviews or shares staff communications.

In the airline sale, a flight attendants' union objected on privacy grounds, MIT Technology Review reported. In Microsoft 365, personal data concentrates in user mailboxes and OneDrive folders, in 1:1 Teams chats, in meeting recordings and transcripts, and in HR and payroll mailboxes and SharePoint sites. Leave the HR mailboxes and sites out, exclude 1:1 chats and recordings unless they are needed, replace names with stable tokens and keep the threads intact. The de-identification guide covers the method.

Microsoft 365 Backup is a restore tool, not an archive you keep

Microsoft sells a separate product, Microsoft 365 Backup, that backs up all or selected SharePoint sites, OneDrive accounts and Exchange mailboxes. It is billed at $0.15 per GiB per month for the data it protects, restores are free, and the recovery window is set on each policy: 3 months, 6 months or 1 to 10 years for SharePoint and OneDrive, and up to 2 years for Exchange.

Microsoft presents it as recovery from ransomware and from accidental or malicious deletion. It says backups are created within the protected services' data boundaries and that "Data never leaves the Microsoft 365 data trust boundary", so the product does not give the company a copy held outside Microsoft 365. Before a closure or a sale, the eDiscovery export above is still the step that puts files in your hands. Google Workspace has the same split between retention and export; see exporting Google Workspace data before you cancel.

Source: Microsoft Learn: Overview of Microsoft 365 Backup

Exporting SharePoint lists and Outlook contacts to Excel

Spreadsheet exports cover lists, not mailboxes. They are useful for registers kept as SharePoint lists (asset logs, project trackers, approvals) and for contact lists.

• SharePoint or Microsoft Lists: from the list's command bar, choose Export, then Export to Excel or Export to CSV. The options appear only when no items are selected.
• Export to Excel downloads a query.iqy file with a one-way connection to the list: Refresh All on the Data tab pulls in later changes, and edits in Excel never go back to the list. Folders are flattened, with Item Type and Path columns added.
• Export to CSV is a static copy of the items in the current view, capped at 30,000 rows, with no connection back to the list; it is not offered for document libraries.
• Outlook contacts: in classic Outlook, File > Open & Export > Import/Export > Export to a file > Comma Separated Values, then pick the Contacts folder. Microsoft documents this CSV route for contacts; for email, use the PST export above.

Sources: Microsoft Support: Export to Excel from SharePoint or Lists, checked 2026-11-14; Microsoft Support: Export contacts from Outlook, checked 2026-11-14

Before you cancel Microsoft 365: a short checklist

Export while the subscription is active and users are still licensed. The guide to exporting company records before closing covers the other systems, and how long to keep business records covers what the law requires you to keep.

When the export is safe, find out what the archive is worth from a few questions, with no files shared.

Not sure whether a buyer or an offer is sound? Origin checks who the buyer is, what the license allows and how the price compares with published deals before anything is signed. Get a free estimate and a second opinion.

• Give one admin an E3 or E5 license and eDiscovery permissions.
• Place a hold or retention policy on mailboxes before deleting any user.
• Export mailboxes, Teams and SharePoint by year, with versions and cloud attachments.
• Download each package within 14 days and check it opens.
• Cancel last, and never delete the subscription outright until the files are verified.