Full Mailboxes

The question it answers: Which mailboxes have reached their send quota?

Note

‘Full’ means the mailbox size has reached its send quota (ProhibitSendQuota); mailboxes close to the quota are not listed, and a mailbox with an unlimited quota is never full. Sizes and quotas are the byte counts Exchange reports (TotalItemSize from Get-MailboxStatistics, one call per mailbox, so large tenants take a while). Discovery search mailboxes are left out. The list is All Mailboxes filtered, so Refresh here reloads All Mailboxes too.

At a glance

Where in the app	Exchange Online › Mailboxes › Full Mailboxes
Workload	Exchange Online
Kind	Table
Data	Read from Microsoft 365 when someone first opens it, then kept for the report cache lifetime (Settings > Data & cache, 1 hour unless changed). It reads through PowerShell (Exchange Online or SharePoint Online), so the first load takes longer than a Graph report.
Licence	Exchange Online.
Report id (API and MCP)	exchange.mailboxes.full

Columns

Column	Key	Type
Display Name	DisplayName	Text
User Principal Name	UserPrincipalName	Text
Primary Address	PrimarySmtpAddress	Text
Mailbox Size (GB)	StorageUsedGB	Text
Max Mailbox Size (GB)	ProhibitSendQuotaGB	Text

What it needs

Licence: Exchange Online.

Application permissions on the IntensiveReports app registration (all permissions):

Permission	API	What it allows	Note
Exchange.ManageAsApp	Office 365 Exchange Online	Manage Exchange As Application	+ View-Only Recipients

Data sources it reads

• PowerShell: Get-ExoMailbox -ResultSize Unlimited
• PowerShell: Get-MailboxStatistics (per mailbox)

Through the API and MCP

GET /ir-api/v1/reports/exchange.mailboxes.full?size=100

An AI assistant reads it with the MCP tool get_report and the id exchange.mailboxes.full. The client needs the Read grant for Exchange Online. See Using the API.