Preconfigured mailbox settings in Exchange Online

​Most companies have specific requirements when it comes to the mailboxes of their users, such as limiting the size of a mailbox. My employer for example had 200MB ones until last year, and upped them to 2GB. With Exchange Online’s whooping 50 GB quota, it’s no wonder that almost everyone is running PowerShell script to adjust it as part of the mailbox provisioning process.

Other commonly configured settings are security/compliance related ones and the maximum size for messages. Well, in Exchange Online obviously there are some restrictions on what you can adjust, and sadly, there are very few settings are available via the Set-MailboxPlan cmdlet:

IssueWarningQuota, ProhibitSendQuota, ProhibitSendReceiveQuota, RoleAssignmentPolicy, RetainDeletedItemsFor

The other parameters and Plan related cmdlets, including the much desired Set-CASMailboxPlan, are entirely unavailable. But still, it might save you some time if you simply preconfigure some of these options in your Exchange Online organization. Here’s how to do it.

First of all, get the list of all the available Mailbox Plans and the relevant settings:

Get-MailboxPlan | ft alias,IssueWarningQuota,ProhibitSendQuota,ProhibitSendReceiveQuota,RoleAssignmentPolicy,RetainDeletedItemsFor

You might also want to check which is the default plan, as any changes to it will be automatically applied to all new mailboxes you create:

Get-MailboxPlan | ft Alias,isDefault

Once you have identified the default plan and decided which changes you want to make, you can adjust them using the Set-MailboxPlan cmdlet:

Set-MailboxPlan planGUID -ProhibitSendReceiveQuota 9.75GB -ProhibitSendQuota 9.5GB -IssueWarningQuota 9GB -RetainDeletedItemsFor 30

For completeness, here are all the other parameters of Set-MailboxPlan, sadly many of the useful ones are not available:

Database
MailboxPlanRelease
ManagedFolderMailboxPolicy
RetentionPolicy
OfflineAddressBook
ApplyMandatoryProperties
ThrottlingPolicy
SharingPolicy
RemoteAccountPolicy
RoleAssignmentPolicy
SKUCapability
AddOnSKUCapability
HiddenFromAddressListsEnabled
UseDatabaseRetentionDefaults
RetainDeletedItemsUntilBackup
DeliverToMailboxAndForward
IsExcludedFromServingHierarchy
LitigationHoldEnabled
SingleItemRecoveryEnabled
RetentionHoldEnabled
EndDateForRetentionHold
StartDateForRetentionHold
RetentionComment
RetentionUrl
LitigationHoldDate
LitigationHoldOwner
CalendarRepairDisabled
MessageTrackingReadStatusEnabled
ExternalOofOptions
RetainDeletedItemsFor
ProhibitSendQuota
ProhibitSendReceiveQuota
RecoverableItemsQuota
RecoverableItemsWarningQuota
CalendarLoggingQuota
DowngradeHighPriorityMessagesEnabled
RecipientLimits
ImListMigrationCompleted
ResetPasswordOnNextLogon
SCLDeleteThreshold
SCLDeleteEnabled
SCLRejectThreshold
SCLRejectEnabled
SCLQuarantineThreshold
SCLQuarantineEnabled
SCLJunkThreshold
SCLJunkEnabled
AntispamBypassEnabled
UseDatabaseQuotaDefaults
IssueWarningQuota
RulesQuota
UserPrincipalName
MaxSafeSenders
MaxBlockedSenders
ArchiveName
JournalArchiveAddress
ArchiveQuota
ArchiveWarningQuota
ArchiveDomain
ArchiveStatus
RemoteRecipientType
QueryBaseDNRestrictionEnabled
UserSMimeCertificate
UserCertificate
CalendarVersionStoreDisabled
AuditEnabled
AuditLogAgeLimit
AuditAdmin
AuditDelegate
AuditOwner
CustomAttribute1
DisplayName
MaxSendSize
MaxReceiveSize
EmailAddressPolicyEnabled
RequireSenderAuthenticationEnabled