Microsoft has announced about new feature that soon it will be possible to add third party storage for Outlook Web App (OWA).

Microsoft is more and more opening the door for third party features. This time they have announced that soon it will be possible, to enable third party storage for OWA.  Today Microsoft has already a great integration between OneDrive for Business and OWA.

However, what that means now for us?

Well, the easiest way to explain, it is to use an example:

In this example case the company, let us name it Contoso. From history reason, Contoso is using few cloud services like Google drive etc. from Google. They just have migrated their E-Mail environment form Google mail to Office 365 by following the article HERE.

All the company documents are still located on Google drive and for company reason this has to stay how it is. However, that means all attachments  which Contoso gets from the users, has to be saved on Google drive. By enabling the third party storage option, our users are able, to add and use the Google drive instead of OneDrive for business.


How to enable?

We can enable this feature by using PowerShell.

As the basic cmdlet we are using the Set-OwaMailboxPolicy and here we set the ThirdPartyAttachmentsEnabled to $true

For the field that can be seen in the following example:

Set-OwaMailboxPolicy -Identity OwaMailboxPolicy-Default –ThirdPartyAttachmentsEnabled $true

Note: depending about our environment, we need to know that third party storage like Dropbox and Google Drive can only be used with an Exchange online subscription.


Enabling by the Office 365 admin center

If you feel more comfortable to change the settings by using the Office 365 admin center, you can follow these steps:

Sign in to your Office 365 admin center and got to Settings > Services and add-ins.

Here we can chose the option Office Online.

Here we activate the option Allow people to use third-party hosted storage services and push Save.

User are now able to use third party storage


After we have made the settings, our users are from this moment able to use their third party storage. How to do that I want to show  with Dropbox example:

After the login to the users OWA, our user needs to select  > Options.

In the Option pane, under Mail > Attachment options, we select Storage accounts.

Here the user can add the third party storage account.



The new possibility to have a free choice for our storage looks like a small thing. However, depends about company policies it can become a big deal. In one hand Microsoft offers us now one more reason to be able to migrate to Office 365, we don’t need to migrate in the same process the files for a third party Cloud provider. This we can do, if we want, in a second step of a migration progress.

If we enable this feature, we have to think on the other hand about the company policy of do we need to prevent, that our users will be able to add not company third party storage services to the company mailboxes. This can be handled by GPO settings.




Photo by Nick Fewings on Unsplash