A Microsoft Office 365 migration moves email, mailbox folders, calendars, contacts, user files, and shared documents when your project includes them. Supported routes also move selected SharePoint and Teams content. Your source platform, migration tools, and agreed scope determine which items transfer and which need separate handling.
This guide covers moves into Microsoft 365 from email hosts, Exchange servers, and file storage, plus moves between Microsoft 365 organizations. Before you approve a quote, check where your data lives and what your team expects to use after the move.
Microsoft 365 migration scope at a glance
Use this overview to discuss each data type with your migration provider. No single email transfer automatically covers every row.
| Data type | Typical destination | What to confirm |
|---|---|---|
| Email and folders | Exchange Online | Mail history, attachments, folders, date filters, and skipped items |
| Calendars and contacts | Exchange Online | A supported migration method and separate handling for shared calendars |
| User files | OneDrive for Business | Source folders, ownership, sharing, and files stored only on devices |
| Shared documents | SharePoint | Libraries, folder structure, permissions, metadata, and version history |
| Teams content | Teams with SharePoint and OneDrive | Files, membership, channels, and message history as distinct tasks |
| Archives and special data | An agreed destination | PST files, public folders, shared mailboxes, and unsupported items |
For an overview of planning, transfer, and user support, read about Piccola Tech’s Microsoft Office 365 Migration Services.
Email mailboxes folders and attachments
Email migration typically transfers messages and mailbox folders into Exchange Online. Include Inbox, Sent Items, and business folders in your scope. Attachments stored inside messages usually transfer with supported messages. A link to a cloud document still depends on the document’s location and access permissions.
The source system matters. Exchange migration methods support mailbox content beyond email. IMAP, a protocol for accessing email, transfers email folders but excludes calendars, contacts, and tasks. Microsoft explains these differences in its email migration overview.
Ask your provider to identify date filters, size limits, and excluded items before transfer. For Microsoft’s native IMAP migration, the documented maximum message size is 35 MB. Other migration methods have different limits. Review the IMAP migration requirements when this route applies.
Calendars contacts and shared scheduling
Supported Exchange migrations move mailbox calendars and contacts. Microsoft’s Google Workspace migration guidance also describes an automated route for transferring mail, calendars, and contacts from Google Workspace.
Do not assume an email-only method includes scheduling data. Microsoft’s Google Workspace route excludes shared calendars and room bookings, among other items. Give shared scheduling its own review.
- Identify personal calendars, shared calendars, and room or equipment calendars.
- Test recurring meetings, organizer details, time zones, and calendar access.
- Separate personal contacts from company directory contacts and distribution groups.
Check meeting links too. Moving a calendar entry does not replace an old conferencing link or confirm its continued availability.
OneDrive migration and user files
OneDrive for Business holds files associated with an individual’s work account. Your file migration scope should identify which device folders, file shares, or cloud locations feed each destination account.
An email migration does not upload files from an employee’s Desktop or Documents folder. Inventory those locations and agree which files belong in OneDrive and which belong in a shared SharePoint library.
For Google Drive sources, Microsoft’s Migration Manager guidance covers files, destination paths, identities, and permissions. Its file compatibility guidance explains conversion of Google Docs, Sheets, and Slides into Word, Excel, and PowerPoint files.
Test converted files your business relies on, especially spreadsheets with formulas and documents with links. Confirm whether the selected route preserves older versions, sharing permissions, and ownership. A successful file copy alone does not prove employees have the right access.
SharePoint migration and shared company documents
SharePoint migration supports shared files and folders, document libraries, and supported lists or site content. The source platform determines which features transfer.
Microsoft’s SharePoint migration documentation covers moving content from on-premises SharePoint and file shares. Supported SharePoint features include files, folders, list items, and selected site features. Existing cloud-to-cloud projects require an appropriate route for those environments.
Treat permissions, metadata, and version history as explicit requirements. Microsoft’s SharePoint Migration Tool settings let administrators choose permission handling and the number of file versions to retain. Test custom pages, forms, and workflows separately instead of assuming a file transfer reproduces their behavior.
Teams migration files messages and collaboration spaces
Teams migration requires more than copying documents. Teams brings together files, conversations, membership, and connected applications.
Microsoft explains where Teams stores files: files uploaded to channels live in SharePoint, while files sent in chats live in OneDrive for Business. Private and shared channels also have separate SharePoint sites, as outlined in Microsoft’s Teams and SharePoint guidance. Include these locations in your inventory.
Message history needs its own migration method. Microsoft documents supported message imports into Teams, including chat and channel content. Coverage depends on the route and tool. Moving the associated files does not transfer conversations automatically.
Confirm the following before accepting “Teams migration” as a line item:
- Which teams, channel types, owners, members, and guests the project covers.
- Which chat and channel messages the chosen method supports.
- How the project handles file links, recordings, tabs, apps, and Planner content.
Data requiring special mapping or separate handling
Mapping connects a source user, folder, or permission to its destination. A file needs the right owner and location, and employees need the correct access after transfer.
Give these items explicit scope entries:
- Shared mailboxes and delegated access, including who needs read and send permissions.
- PST archive files, public folders, and external archives requiring a separate import or migration route.
- Former employees’ data and files owned by accounts without a matching destination user.
- Shared links, external guests, and folders with access rules different from their parent folders.
- Custom SharePoint content, application data, and files the migration tool skips.
When moving between Microsoft 365 organizations, review Microsoft’s tenant-to-tenant planning guidance. Identity mapping, licensing, and the selected workloads affect the project. Moving data also requires separate planning for account settings, DNS, Outlook setup, security controls, and backup.
Define the scope before your migration starts
Ask each department where it keeps the information it needs each day. Then record the answers in your Microsoft Office 365 Migration checklist.
- Inventory your sources. Include mailboxes, archives, shared drives, device folders, sites, and collaboration tools.
- Assign destinations and owners. Identify the mailbox, OneDrive account, SharePoint library, or team for each source.
- Confirm inclusions and exclusions. Specify date ranges, versions, permissions, and separate handling for unsupported items.
- Agree on validation. Review item-level errors, sample files, calendars, and user access before closing the project.
For example, a 15-person business moving from Google Workspace needs separate scope entries for Gmail, calendars and contacts, individual Drive files, shared drives, and shared calendars. An email-only quote does not cover every entry. This example shows why the data list matters more than the user count alone.
Read how to prepare your business for a Microsoft Office 365 Migration before scheduling the move. After cutover, use our post-migration Microsoft 365 security checklist to review account protection and recovery planning.
Frequently asked questions
Define your Microsoft 365 migration with Piccola Tech
Not sure what your Microsoft 365 migration should include? Contact Piccola Tech or book a free, no-obligation consultation for help defining the scope and next steps. We help small businesses in NYC and nearby areas plan their move, validate access, and support users after cutover.
