New OWA Files View Makes Attachments More Accessible

Quickly Find Attachments in Primary Mailbox

In the run-up to the Christmas holidays, you might have missed Office 365 notification MC198342 posted on 17 December to announce the advent of the OWA Files view. According to Microsoft 365 Roadmap item 59643 this is “a view of all the files sent and received as attachments in your inbox.” In reality, the Files view enables quick access to every sent or received attachment in every folder in your primary mailbox.

The feature is now rolling out to tenants and should be available throughout Office 365 by the end of March. You’ll know if it’s available when the Files icon shows up in OWA’s module switcher (Figure 1). Clicking the icon takes you to https://outlook.office.com/files/.

The Files icon in the OWA module switcher
Figure 1: The Files icon in the OWA module switcher

Microsoft hasn’t said if they will add this feature to OWA for Exchange on-premises. My feeling is that this is doubtful.

The Files View

The Files View presents attachments found in a mailbox in five columns, each of which is sortable. The default sort is by received date (newer to older), while Figure 2 shows attachments sorted by name (Z to A).

OWA Files View (of attachments)
Figure 2: OWA Files View (of attachments)

Newly received or sent attachments don’t show up immediately in the view.

If you select an attachment, OWA opens it and the message it belongs to in a viewer. You can hide the message if you want to concentrate on the attachment.

Types of Attachments

By default, all types of attachment are shown. OWA differentiates between Files (Office documents, PDFs, text, email, and other non-graphic types) and Photos (files in graphic formats like JPEG or PNG). When browsing photo attachments, choosing Tiles rather than a list can help locate the right attachment faster (Figure 3).

 Viewing photo attachments as tiles in OWA Files
Figure 3: Viewing photo attachments as tiles in OWA Files

Filtering Attachments

You can choose to see all attachment types or switch between Files and Photos using the options in the left-hand navigation pane or the Filter drop-down (Figure 4), which allows you to select exactly what you want to see. The date range part of the filter is very useful when you want to find attachments sent in a specific period. You can combine a date range with filters for specific file types.

Filters for OWA Files
Figure 4: Filters for OWA Files

To refine the view further, you can input search terms into the search box. OWA will apply the search to the items in the view and display what it finds.

No Archived Attachments

OWA’s Files view only shows attachments stored in the primary mailbox. Attachments moved into archive mailboxes (not to be confused with the Archive folder in mailboxes) are not shown in the Files view. You’ll have to open the archive mailbox and use a search to find information stored there. This isn’t surprising because archive mailboxes are intended to hold information that is not needed very often.

The Substrate is the Key

Microsoft dipped their toes into a Files view for OWA with “group files” for Office 365 Groups in 2016. That feature is less functional than the generalized Files view now being introduced. In both cases, the features depend on the capture and storage of information by the Office 365 substrate. Hidden folders in user mailboxes (like GraphFilesAndWorkingSetSearchFolder) hold metadata and copies of attachments. OWA uses this data for fast access to information and to avoid the need to scan a mailbox looking for messages with attachments.

Poking around the folders in the “non interpersonal messaging” (aka Non-IPM subtree) part of an Exchange Online mailbox with a tool like MFCMAPI reveals that cloud mailboxes hold a lot more information than their on-premises counterparts. The overall size of these mailboxes is much larger than you’d expect. Features must be paid for with resources, and cloud storage is cheap (except for SharePoint Online).


OWA Files is an example of a new feature that may or may not make a difference to you. But it’s good to know about stuff like this, which is why we keep an eye on Office 365 developments for you and document the most important in the Office 365 for IT Pros eBook. Subscribe today to stay informed.

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