What is the difference between stage 1 and stage 2?
N/A
Even if the mailboxes or users already exist in the target, the archive linkage (the association between a user and their archive) isn’t automatically tied to the migrated data.
Stage 1 (Copy/Sync phase):
AS copies archive data from the source archive (e.g., SourceOne, Enterprise Vault, etc.) into the target archive (e.g., Exchange Online, Enterprise Vault, etc.).
During this stage, users are still pointing to their source archive when they try to open archived items (e.g., Outlook shortcuts, stubs, compliance lookups).
The target system now has data, but users and apps don’t yet know to use it.
Stage 2 (Switch phase):
This is the cutover. AS (with its agents, scripts, or connectors) updates the user-to-archive mapping in the target environment.
It flips shortcuts/stubs in mailboxes so they now resolve against the new target archive instead of the source.
It also updates permissions, search indexes, and sometimes policies in the target so the user’s Outlook/OWA experience now points only to the target.
After this point, the source archive can be decommissioned.
Depending on the source and target systems, it may include:
Updating Archive Links
For systems like Enterprise Vault → Enterprise Vault migrations, AS will re-map user accounts to their new archive IDs.
Stub/Shortcut Re-linking
If stubs are migrated (instead of “shortcutless”), AS replaces the hidden message properties so the stubs open the item from the target archive.
Permissions Synchronization
Ensures any delegated/archive access rights are re-applied in the target.
Final Delta Sync
Copies any items that were ingested during the migration window (to ensure no data loss).
Switch Confirmation & Lockout of Source
Users are now expected to use the target archive only. Access to the source archive is blocked to avoid confusion.
✅ So even though the users exist in the target already, their archive pointers do not.
That’s why Stage 2 Switch is required — it’s the step that makes the target archive “live” for end-users and applications.
