What Is Online Archive in Microsoft 365?
Online Archive is a separate mailbox linked to the user account where old emails are stored automatically.
Step 1: Connect to Exchange Online PowerShell
Open Windows PowerShell as Administrator.
Install Exchange Online module (only once)
Install-Module ExchangeOnlineManagement
Connect to Microsoft 365
Connect-ExchangeOnline
Step 2: Enable Online Archive for the User
Follow the blog: https://clients.activeservers.in/knowledgebase/290/How-to-Enable-Archive-Storage-for-Microsoft-365-BasicorStandard-Plans.html
Verify archive is enabled:
Get-Mailbox user@domain.com | Select ArchiveStatus
If it shows:
Active
Step 3: Enable Organization Customization (One-Time)
Microsoft 365 tenants block retention commands by default.
Run this once only:
Enable-OrganizationCustomization
Wait 2–5 minutes before continuing.
Step 4: Create a Retention Policy Tag (Move to Archive)
This tag tells Microsoft:
“Move emails older than X years to archive”
Example: Move emails older than 2 years
New-RetentionPolicyTag -Name "MoveToArchive_2Years" `-Type All `-RetentionAction MoveToArchive `-AgeLimitForRetention 730
730 days = 2 years
Step 5: Create a Retention PolicyNew-RetentionPolicy -Name "ArchivePolicy_2Years"Step 6: Link the Tag to the Policy
Set-RetentionPolicy "ArchivePolicy_2Years" `-RetentionPolicyTagLinks "MoveToArchive_2Years"
Step 7: Assign Policy to a Specific UserSet-Mailbox user@domain.com -RetentionPolicy "ArchivePolicy_2Years"
Step 8: Confirm Policy Is AssignedGet-Mailbox user@domain.com | Select RetentionPolicyIf you see:
ArchivePolicy_2Years
It is correctly applied.
Step 9: Monitor Archive Progress
Check archive mailbox sizeGet-MailboxStatistics user@domain.com -Archive |Select DisplayName,TotalItemSize,ItemCount
Example output:In-Place Archive - User6.124 GB3918 items
Check last processing timeGet-MailboxStatistics user@domain.com |Select DisplayName,LastProcessedTime
Recent time = policy is still running.
