Exchange Online mailbox inspection cheat sheet
Connect to Exchange Online and review mailbox identity and quotas.
ExchangeOnlineManagement module; Exchange Online PowerShell.
Updated · Exchange Online · 7 min read
| Command | What it does |
|---|---|
Connect-ExchangeOnline | Open an authenticated Exchange session |
Get-EXOMailbox -Identity 'user@example.com' | Inspect mailbox identity |
Get-EXOMailbox -Identity 'user@example.com' -Properties IssueWarningQuota,ProhibitSendQuota | Read mailbox quota settings |
Disconnect-ExchangeOnline -Confirm:$false | Close the PowerShell session |
Walkthrough
Use an approved Exchange Online account with the required RBAC read permissions. Replace user@example.com with the target mailbox.
Step 1: Open an authenticated Exchange session
Connect-ExchangeOnline
Complete interactive authentication using your approved admin identity. Verify you are connecting to the intended organization before inspecting recipients.
Step 2: Inspect mailbox identity
Get-EXOMailbox -Identity 'user@example.com'
Compare primary SMTP address and recipient type with the reported mailbox. A mail-enabled user and an Exchange Online mailbox are different recipient types.
Step 3: Read mailbox quota settings
Get-EXOMailbox -Identity 'user@example.com' -Properties IssueWarningQuota,ProhibitSendQuota
Request the non-default quota properties explicitly. Compare configured quotas with actual mailbox size before concluding that quota enforcement is causing the issue.
Step 4: Close the PowerShell session
Disconnect-ExchangeOnline -Confirm:$false
End the session after capturing necessary findings. This disconnects the administrative session; it does not disconnect mailbox users.