Tag Archives: Exchange

Microsoft 365 ownerless group policy to send more than 10,000 notifications

It is known that a single Microsoft Exchange account is not sending more than 10k emails per day.

It is also know that once activated – Microsoft 365 groups ownerless policy will be sending notifications for all groups in scope to specified number of group members within 24 hours.

The question is: what if there are more than 10,000 notifications to send (e.g. 4,000 ownerless groups and the policy is configured to send notification to 3 members per group – that gives us 12,000 notifications to send)? Would the policy send 10k notifications and the rest 2k notifications the next day?

I’m conducting an experiment. I created 10k groups in my lab tenant with one owner and 3 random members. Then I configured a policy that is sending notification to a 3 most active members (in this case – random members). And then I made all these groups ownerless by deleting the single owner Id from Azure AD (Microsoft Entra).

Here is what I got from users perspective:

useruser groups
got messages
day 1
got messages
day 2
got messages
1 Roger50121374
2 Dick50391349
3 Bob51083412
4 Bapu49081376
5 Stas49961437
6 David49591377

Here is what audit log says:

Events “OwnerlessGroupNotified” day 1: 4949
Events “OwnerlessGroupNotified” day 2: 95
Events “OwnerlessGroupNotified” total: 5044
Each event details says 3 members were notified.

It seems like groups are selected by policy in random order.

Massive E-mails sending was started 43 minutes after midnight UTC

“OwnerlessGroupNotified” were logged at the rate of
1925 events during 1-st hour,
2029 events during 2-nd hour,
785 events during 3-rd hour,
176 events during 4-th hour,
26 events during 5-24 th hour,
95 events during next 25-48 hours
so max rate was one event every 3 seconds in the beginning (or 1 e-mail per second) …


Search Unified Audit Log Daemon Job

How to run “Search-UnifiedAuditLog” in unattended way, i.e. non-interactive.
What are the minimal permissions required?

The PowerShell code:

$clientId = ""
$cPwd = ConvertTo-SecureString -String "" -AsPlainText -Force

$cPath = ""C:\Users\UserName\Certificates\Cert.pfx""
$organization = "contoso.onmicrosoft.com"

Connect-ExchangeOnline -CertificateFilePath $cPath -CertificatePassword $cPwd -AppID $clientId -Organization $organization

[DateTime]$start = [DateTime]::UtcNow.AddMinutes(-45)
[DateTime]$end = [DateTime]::UtcNow
$resultSize = 1000

$results = $null
$results = Search-UnifiedAuditLog -StartDate $start -EndDate $end -ResultSize $results.Count
$results | Select-Object RecordType, CreationDate, UserIds, Operations -First 3

Disconnect-ExchangeOnline -Confirm:$false


The error “The term ‘Search-UnifiedAuditLog’ is not recognized”:

Search-UnifiedAuditLog: C:\scripts\PowerShell.auth\Search-AuditLog-w-App.ps1:16:12
Line |
16 | $results = Search-UnifiedAuditLog -StartDate $start -EndDate $end -Re …
| ~~~~~~
| The term 'Search-UnifiedAuditLog' is not recognized as a name of a cmdlet, function, script file, or executable
| program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.

means a proper administrative role (e.g. “Exchange administrator”) is not assigned.