Skip to main content

Expanded Folder Age and Attachment reporting for Exchange / Office 365 Mailboxes with EWS and Powershell

Folder Item numbers, size's and Attachment Item Numbers, types and sizes are one of the Mailbox statistics that is useful when your trying to look at how and why a mailbox is growing or why your mailbox performance might be declining if you have a large number of folder items. With the recent increases in Mailbox size quotas  in Office365 it can be easy to become quite indifferent to how quickly your mailbox might be growing. For example if you have 100GB quota the lazy mindset (which I admit to being a part of) can be to just keep everything you get via mail (or stack it and rack it). If your users are not able to take advantage of cloudy attachments (or the users refuse to change their use habits) the nature of expanding file sizes means a sharper growth curve for Folder Items and Attachments.

The traditional way of tracking Mailbox sizes is to use Get-MailboxStatistics and Get-MailboxFolderStatistics for which there are many good scripts around that give a good overview of what is in a Mailbox or Folder. For a deeper dive into what  is in messages in a particular folder where you are seeing growth then using a Mailbox API like EWS (or REST) can be useful. In the past I've posted a few scripts for doing Attachment and Item level statistics which where in need of some updating which is what I've done with this post

Script Approach 

For this script I've used EWS as it is universal across OnPremise and Office365 from Exchange 2010 up. I do have two different versions of this script however because Office365 and Exchange 2016 allows you to have reference attachments (cloudy attachments) so some slightly different code is needed and the latest compiled version of the EWS Managed API which is only available from GitHub is needed so statistics can be compiled successfully for these type of Attachments. For the Item level processing side of the script it will process every item in a folder firstly using the EWS FindItems operation which will return a minimal results set of Items and Sizes and then for those items with Attachments another batch operation is used to get the metadata for the attachments which will include the Attachment name (which we can then derive the attachment type from using the file extension name) and the size of the attachment. If its a cloudy attachment then this is processed separately. I haven't included any code to call out to OneDrive to get the filesize for the cloudy attachments but its possible to do this with some extra code (generally you would want to do this asynchronously while processing the Exchange attachments).

The Results the script produces is the following html report



The script writes its result sets out in JSON, I've then used the Tabulator JavaScript library http://tabulator.info/ which can turn JSON datasets into well formatted tables and offer sorting options so its quite easy to create a more user friendly results set then just a plain CSV file which I usually use. Currently the script will report on just one particular folder as I envisaged that it would be best used in conjunction with other scripts (that utilize Get-MailboxStatistics and Get-MailboxFolderStatistics eg take your pick from https://social.technet.microsoft.com/Search/en-US/office?query=Mailbox%20size%20report ) where you identify a particular Mailbox or  folder you want to investigate more thoroughly as this script can take some time to run. I also have two defined modes where you can process Inline Attachments (which are primary just image files) or skip the processing of Inline attachments which will make the script run a lot faster because of the number of Messages that have inline attachments.

Some Examples of running the script on the Inbox folder without processing Inline attachments


Import-Module .\AttachmentStats.ps1
Invoke-MailboxFolderAttachmentReport -MailboxName gscales@dataru mble.com -FolderPath \Inbox -Verbose

Or with processing Inline attachments

Import-Module .\AttachmentStats.ps1
Invoke-MailboxFolderAttachmentReport -MailboxName gscales@dataru mble.com -FolderPath \Inbox -IncludeInline -Verbose
The report will be saved to the same path as the script module is located.

The regular version of the script can be found on GitHub https://github.com/gscales/Powershell-Scripts/blob/master/AttachmentStats.ps1

The cloudy version of the script can be found on GitHub here https://github.com/gscales/Powershell-Scripts/blob/master/AttachmentStats-Cloudy.ps1 

The cloudy version will require the following EWS Managed API version https://github.com/gscales/Powershell-Scripts/raw/master/Microsoft.Exchange.WebServices.dll to be located in the same directory as the script module.

The Cloudy version will produce a separate table of cloudy attachment stats eg



Hire me - If you would like to do something similar to this or anything else you see on my blog I'm currently available to help with any Office365, Exchange or Active Directory related development work or scripting, please contact me at gscales@msgdevelop.com(nothing too big or small).


Popular posts from this blog

Testing and Sending email via SMTP using Opportunistic TLS and oAuth in Office365 with PowerShell

As well as EWS and Remote PowerShell (RPS) other mail protocols POP3, IMAP and SMTP have had OAuth authentication enabled in Exchange Online (Official announcement here ). A while ago I created  this script that used Opportunistic TLS to perform a Telnet style test against a SMTP server using SMTP AUTH. Now that oAuth authentication has been enabled in office365 I've updated this script to be able to use oAuth instead of SMTP Auth to test against Office365. I've also included a function to actually send a Message. Token Acquisition  To Send a Mail using oAuth you first need to get an Access token from Azure AD there are plenty of ways of doing this in PowerShell. You could use a library like MSAL or ADAL (just google your favoured method) or use a library less approach which I've included with this script . Whatever way you do this you need to make sure that your application registration  https://docs.microsoft.com/en-us/azure/active-directory/develop/quickstart-register-

How to test SMTP using Opportunistic TLS with Powershell and grab the public certificate a SMTP server is using

Most email services these day employ Opportunistic TLS when trying to send Messages which means that wherever possible the Messages will be encrypted rather then the plain text legacy of SMTP.  This method was defined in RFC 3207 "SMTP Service Extension for Secure SMTP over Transport Layer Security" and  there's a quite a good explanation of Opportunistic TLS on Wikipedia  https://en.wikipedia.org/wiki/Opportunistic_TLS .  This is used for both Server to Server (eg MTA to MTA) and Client to server (Eg a Message client like Outlook which acts as a MSA) the later being generally Authenticated. Basically it allows you to have a normal plain text SMTP conversation that is then upgraded to TLS using the STARTTLS verb. Not all servers will support this verb so if its not supported then a message is just sent as Plain text. TLS relies on PKI certificates and the administrative issue s that come around certificate management like expired certificates which is why I wrote th

The MailboxConcurrency limit and using Batching in the Microsoft Graph API

If your getting an error such as Application is over its MailboxConcurrency limit while using the Microsoft Graph API this post may help you understand why. Background   The Mailbox  concurrency limit when your using the Graph API is 4 as per https://docs.microsoft.com/en-us/graph/throttling#outlook-service-limits . This is evaluated for each app ID and mailbox combination so this means you can have different apps running under the same credentials and the poor behavior of one won't cause the other to be throttled. If you compared that to EWS you could have up to 27 concurrent connections but they are shared across all apps on a first come first served basis. Batching Batching in the Graph API is a way of combining multiple requests into a single HTTP request. Batching in the Exchange Mail API's EWS and MAPI has been around for a long time and its common, for email Apps to process large numbers of smaller items for a variety of reasons.  Batching in the Graph is limited to a m
All sample scripts and source code is provided by for illustrative purposes only. All examples are untested in different environments and therefore, I cannot guarantee or imply reliability, serviceability, or function of these programs.

All code contained herein is provided to you "AS IS" without any warranties of any kind. The implied warranties of non-infringement, merchantability and fitness for a particular purpose are expressly disclaimed.