While this list of scenarios does not cover every possible option, it covers the primary Microsoft approaches to migrations. There are third party tools from vendors such as BitTitan and SkyKick that can also assist if one of the options below doesn't meet your requirements.
This highlights the different approaches that can be taken based on what the source server is, which means the version of Exchange you are migrating from dictates the migration options that will work.
PST Migration Features
- Works with customers using Outlook independent of mail systems
- Enables user driven or IT migration
- Users can migrate content on demand
- Migrates mail, calendar, contacts, tasks
- New mailbox in cloud – new Outlook profile and caching
PST Capture Tool
- Stand alone tool to capture and migrate PST data
- Option to import to mailbox or archive
- Requires central PST capture console installation
- Agent required on client computers for capture and migration
IMAP Features And Benefits
- Works with a large number of source mail systems
- Works with on-premises or hosted systems
- Users can be migrated in batches
- On-premises migration tool is not required
IMAP Requirements And Limitations
- On-premises migration tool is not required
- Access to IMAP ports (TCP/143/993)
- Users + mailboxes must be provisioned prior to migration
- Bulk provisioning, CSV parser, manual, etc.
- SMTP domains configured in O365 tenant
- Gather user credentials or setup admin credentials
- Prepare a CSV file with list of users
- EmailAddress, UserName, Password
- Max of 50,000 rows
- Max 10 MB in size
IMAP Data Migration Scope
- Migrated
- Mail messages (Inbox and other folders)
- Maximum of 500,000 items
- Possible to exclude specific folders from migration (e.g. Deleted Items, Junk E-Mail)
- Not Migrated
- Contacts, Calendars, Tasks, etc.
- Excluded folders
- Folders with a forward slash ( / ) in the folder name
- Messages larger than 35 MB
Cutover Features And Benefits
- Simple and quick migration solution
- High-fidelity solution – all mailbox content is migrated
- Suited to organizations who want a full migration all at once
- Users are provisioned automatically during migration
- Works with Exchange 2003 and newer
- Works with on-premises or hosted Exchange systems
- Identity management in the cloud (at least initially)
- On-premises migration tool is not required
Cutover Requirements And Limitations
- Up to 1000 mailboxes in source system
- Outlook Anywhere service on source system
- (must have SSL certificate issued by a public CA)
- Migration Account with Full Access or Receive-As permissions to all mailboxes that will be migrated
- Directory Sync tool initially disabled in O365 tenant
- SMTP domains configured in O365 tenant
Cutover Accounts And Passwords
- Accounts Provisioning
- Migration creates users, mailboxes, DLs and contacts
- Migration enables replies to migrated messages (i.e. provision process brings over the Legacy DNs)
- Passwords
- No access to passwords from source directory
- New passwords created for all users
- A link to download passwords is sent to admin
- Users must change password on their first login
Cutover Data Migration Scope
Migrated
- Mail messages and folders
- Rules and categories
- Calendar (normal, recurring)
- Out-of-Office settings
- Contacts
- Tasks
- Delegates and folder perms
- Outlook settings (e.g. favorites)
Not Migrated
- Security Groups, DDLs
- System mailboxes
- Dumpster
- Send-As Permissions
- Messages larger than 35 MB
Cutover Data Migration Scope
- Partial migrations are not possible (folder exclusion, time range)
- Mailboxes enabled for Unified Messaging cannot be migrated
- Existing cached-mode files (OST files) cannot be preserved
Cutover User Experience
- Admin needs to distribute new passwords to users
- Users create their new Outlook profile using O365 username and new passwords (Autodiscover)
- All mail is downloaded from the Office 365 mailbox (i.e. the OST file must be recreated)
Staged Features And Benefits
- Simple and flexible migration solution
- High-fidelity solution – all mailbox content is migrated
- Suited to organizations who want to migrate in batches
- Source of Exchange 2003 or 2007 only
- Users are provisioned with Directory Sync prior to migration
- No limit on the number of mailboxes
- Users can be migrated in batches (up to 1000 per batch)
- Identity management on-premises
- On-premises migration tool is not required
Storage Requirements And Limitations
- Outlook Anywhere service on source system (must have SSL certificate issued by a public CA)
- Migration Account with Full Access or Receive-As permissions to all mailboxes that will be migrated
- Directory Sync tool enabled in O365 tenant
- SMTP domain(s) configured in O365 tenant
- Does not work with Exchange 2010 or 2013
Storage Accounts And Passwords
- Accounts Provisioning
- For every on-premises mailbox to be migrated there needs to be a MEU or Mailbox in Office 365
- Migration tool relies on DirSync to do provisioning
- Passwords
- Target mailbox passwords must be specified for all the users
- Administrators can force users to change passwords on first login
Staged Batch File
- CSV format
- EmailAddress, Password, ForceChangePassword
- One user per line
- Max of 1000 users in each CSV
- Smart-check against the Office 365 directory
Staged Data Migration Scope
Migrated
- Mail messages and folders
- Rules and categories
- Calendar (normal, recurring)
- Out-of-Office settings
- Contacts
- Tasks
- Delegates and folder perms
- Outlook settings (e.g. favorites)
Not Migrated
- Security Groups, DDLs
- System mailboxes
- Dumpster
- Send-As Permissions
- Messages larger than 35 MB
Staged Data Migration Scope
- Partial migrations are not possible (folder exclusion, time range)
- Mailboxes enabled for Unified Messaging cannot be migrated
- Existing cached-mode files (OST files) cannot be preserved
Staged User Experience
- Admin needs to distribute new passwords to users
- Users create their new Outlook profile using O365 username and new passwords (Autodiscover)
- All mail is downloaded from the Office 365 mailbox (i.e. the OST file must be recreated)