Mailbox License Limit

Overview

The Mailbox License Limit indicator reports that the number of mailboxes discovered in your environment has exceeded the number your ENow licence covers.

This is about your ENow licence, not your Microsoft licences. EMS also reports extensively on Microsoft 365 licensing — License Cost, Licensed Users, Candidates for License Optimization and similar. Those reports describe your Microsoft subscription. This alert describes your entitlement to use EMS, and the two are unrelated. If you arrived here from a licence report rather than from an alert, you are probably looking for the wrong page.

Monitoring Benefit

The Mailbox License Limit check compares the number of user mailboxes EMS discovers against the number your licence permits, and warns you before the overage begins to affect mailbox reporting. It gives you a grace period to resolve the difference rather than failing silently or stopping without notice.

Which mailboxes count towards the limit

This is the part that most often explains an unexpected overage — the count is not simply "every mailbox in the organisation".

In a hybrid environment it is the combined figure that is compared against your licence, which is worth keeping in mind when neither side looks over the limit on its own.

What happens when the limit is exceeded

There are two stages, and the wording on screen tells you which one you are in.

During the grace period. A note appears at the bottom of the main monitoring page reading "A mailbox license limit has been exceeded. Click here for details." Following that link opens the main reporting page, where a note appears above the report section — the Mailbox Reports section for on-premises Exchange, or the Office 365 reports section for Microsoft 365. That note reads:

Your mailbox license limit has been exceeded. When this license error is 14 days old, mailbox reports will no longer be generated.

After the grace period. Once the licence error is more than 14 days old, the note changes to:

Your mailbox license limit has been exceeded for more than 14 days. Mailbox reports are no longer being updated.

At that point the Top 20 Mailbox report is no longer accessible.

How do we verify the monitoring test results?

1. Read the note, not just the indicator. The two messages above are the quickest way to establish whether you are inside the 14-day window or past it, and they appear on the reporting page rather than the dashboard.

2. Force the mailbox licence count to refresh. Mailbox licence processing runs as part of report processing rather than on the monitoring cycle, so a change you have just made will not be reflected immediately. To force it, open the Top 20 Mailbox report and click Update Now.

Note that once the grace period has expired this report is no longer accessible, so if you need to force a refresh, do it before the window closes.

3. Check when report processing last ran. Licence processing for Active Directory and Lync or Skype for Business users happens after nightly report processing, under Report Dispatcher > Options.

4. Reconcile the count yourself. Compare the mailbox count EMS reports against your own count, applying the inclusion rules in the table above. The most common causes of an apparent discrepancy are shared or resource mailboxes being counted in the manual figure when EMS excludes them, and — in hybrid — only one side of the environment being counted.

Common warning or error results, and potential solutions

Related

• EMS Server License Limit — the equivalent check for licensed server count.