Wednesday, September 02, 2015

Time to Manage your Unmanaged Mailboxes!!!

Recently I came across on interesting issue that made me write this post, In a large Organization with "n" number of mailboxes its tough to identify Mailboxes that are going to get affected by an unexpected issue before hand and if the mailbox is not monitored by someone "unmanaged" the situation becomes even tough as the warnings that are sent by the Exchange Server are ignored, Appropriate action will not be taken on time and the issue becomes inevitable.

Let's get in to our issue, In my environment one of the Mailbox that was designated for a particular application related task started to trigger NDR for end users who send E-mail to the mailbox and all the settings on the mailbox is appropriate, it had enough free Mailbox storage available to accommodate the E-mails but all the E-mails messages sent are un-deliverable.

Below is the Vital Message on the  NDR

The recipient's email system isn't accepting messages now. Please try resending your message later or contact the recipient directly.

Remote Server returned '554 4.3.2 mailbox busy; STOREDRV.Deliver.Exception:StoragePermanentException.MapiExceptionMaxObjsExceeded; Failed to process message due to a permanent exception with message Cannot complete delivery-time processing

Upon investigation we came to know that the Mailbox Folder where these E-mails are landing i.e, Inbox in my case it has exceeded the Maximum number of messages per mailbox folder which is 1 Million Messages per Exchange Online Limits description.

Ran the below Shell to check the Item count

Get-MailboxFolderStatistics TestMailbox | select Name, Folder*,  Items* | fl

Once we narrow down the issue we moved the old E-mails from the mailbox, post this the Mailbox started to receive E-mails are normal. We actively assigned a Owner for the mailbox to Monitor it as a next step.

*There may be more Mailboxes similar to the above one and Assigning a owner to Monitor each of them is not feasible and we may jump and take care as an when required, Want to avoid this, Read further...

This issue was a brainstorming one, that triggered us to generate the report for all the mailboxes are having Larger Item Count and validate the Top ones and analyze whether any Folder contains items that are nearing the Threshold and advice the end users to move the E-mails to other folders or archive them as needed.

You can utilize my Exchange Online Mailbox Usage Report Script to get the Item count and take action as stated above, You can tweak the script to include more results as needed. Though this task is quite painful, its a good move on our part as Admins to avoid upcoming issues proactively.

*There may be other Scenarios similar to this might arise and its always good to review the Exchange Online Limits and perform Periodic Audits inside the environment to ensure that your end user experience is not impacted and you get your environment inline with Microsoft best practices.

As the Blog title says "Always Manage your Unmanaged Mailboxes" and the Time is now!!!

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