Copilot said:
Copilot
Here’s a clear, admin-focused explanation + steps for enabling Auto‑Expanding Archiving in Microsoft 365 E3:
✅ What is Auto‑Expanding Archiving (E3)
- Automatically adds more storage to the archive mailbox when it gets full
- Starts at ~100 GB archive → grows up to ~1.5 TB per user
- Expansion happens when archive reaches around 90 GB
👉 Result: users never run out of archive space
⚠️ Important before enabling
- ✅ User must already have Archive Mailbox enabled
- ✅ Requires E3 / E5 / Exchange Online Plan 2
- ❗ Cannot be disabled after enabled
- ❗ Must use PowerShell (NOT Admin Center GUI)
🔧 How to Enable (Step-by-Step)
1. Connect to Exchange Online
2. Enable for ONE user
3. Enable for ALL users (organization-wide)
(Optional: apply to existing users)
4. Verify status
👉 Should show:
📊 What happens after enabling
| Situation | Before | After |
|---|---|---|
| Archive full | Stops at ~100 GB | Auto grows |
| Max storage | Limited | ~1.5 TB |
| Admin work | Manual cleanup | Automatic |
| User impact | Mailbox full risk | No storage issues |
⏱️ Behavior after enabling
- Extra storage is NOT immediate
- It expands gradually when needed (can take days/weeks)
✅ Simple summary
Enable Auto‑Expanding Archiving =
Archive mailbox grows automatically up to ~1.5 TB, no more “mailbox full”.
If you want, I can show you: ✅ how to auto-move emails (e.g. older than 1 year → archive)
✅ or check which users are already using archive space
