Office 365 – Can OWA Be A Replacement For Outlook?

I’ve had a few clients recently that have asked about using OWA instead of Outlook as their primary mail client. It’s a valid question given that users are very familiar with web-based email and likely use a similar interface with their personal email. If OWA meets all of your users’ needs, using OWA can help to reduce the installed applications that have to be maintained and supported on each user’s workstation.
Microsoft has consistently delivered the message that the OWA interface will likely see updates and enhancements more quickly than the Outlook client. While Office 2016 helps Outlook catch up in a few areas, there are still differences between the two interfaces.
Below are some observations when trying to use OWA as replacement for Outlook.

What’s In A Name?

Just to get it out of the way, OWA has technically been renamed “Outlook on the Web” although I don’t believe there’s consensus yet on what acronym to use (OotW?, OW?) if any at all. That said, whether you call it “Outlook Web Access”, “Outlook Web App” or “Outlook on the Web”, we all know we’re talking about the web interface through which you access your Exchange Online mailbox.

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As you can imagine, the web browser you use plays a role in your OWA experience. You’ll want to use the most current version of Internet Explorer for the most optimal experience. Other current browsers will work with small nuances but an outdated browser will throw OWA into the pretty limited “light mode” (Internet Explorer 9 will be limited to “light mode” beginning in January 2016). Even the latest and greatest Microsoft Edge has some limitations when it comes to OWA.

Cloud First

Since OWA is essentially a component of Exchange Online, it’s logical that features are easier to roll into the cloud service than it is getting them into the Office suite. For this reason, you see things like “Office 365 Groups”, “Clutter”, and the new “Pin” and “Sweep” actions in OWA before they appear in Outlook. Users of Office ProPlus likely have a better chance of seeing some of these new features on a more routine basis than those running MSI installations of Office that get patched on a less frequent cycle.

OWA As Your Primary Mail Client

Here are some of deficiencies observed when trying to use OWA as a replacement for Outlook:

Calendar Notifications – Most people I know pretty much live off their calendar alarms. If I have a meeting where the alarm has been removed for some reason, there’s a good chance I’ll overlook it on my schedule. In Outlook, the calendar alarms are pretty front and center by default, there’s almost no missing them. In OWA, the alarms can be overlooked when you’re running multiple tabs or browser sessions. Additionally, it takes some training to get to the point where you realize that closing your browser means closing your mail client and thus your alarm notifications. Given we’re probably getting the alarm notification on our phone, tablet or watch, perhaps this isn’t that big of a deal but it’s a change in what users are used to.
ICS File Import – If you receive an ICS file as an attachment, OWA cannot import this into your calendar. Depending on your communication partners, this could be a big issue. I generally don’t see ICS files aside from registering for webinars or from our travel reservations system.
Conversation View – The “Conversation View” feature seems to be one that users either love or hate. Personally, I’m not a big fan of the view and OWA does provide an option for users to disable it. Unfortunately, disabling Conversation View is a “per-folder” setting and has to be done on each folder.
Email Signatures – While I tend to keep the content in my email signature pretty limited, it’s not uncommon for users to want to put some type of image in their signature. You can argue that this is just cluttering up mailboxes but it’s something that people are used to doing in Outlook. In OWA, you can’t simply paste an image into the signature, it needs to be a link to an image with an externally accessible URL. I have seen some mixed results with this one where you can paste the image in the signature but then it doesn’t send properly for some reason.
Pasting of Images – Pasting images from the clipboard into the body of a message in OWA can also be a bit hit or miss. It seems to be dependent upon the source content. Otherwise you can use the option to import an image from a file but when you’re used to pasting screenshots directly, saving to file first and importing is far from efficient.
Public Folder Coexistence – If you’re running in an Exchange Hybrid environment with Public Folders on-premises made accessible to cloud users, you should be aware that these cannot be accessed via OWA.
Retention Policy Tags – If you use Personal Tags in your Retention Policy, users will not see these tags by default within the right-click menu. The user will need to go to “Options” | “Mail” | “Automatic Processing” | “Retention Policies” and then select the tags they want added to the right-click menu.
Access to PSTs – No one wants to acknowledge that they have PSTs in their environment but it’s almost always the case that they do. Users will have PSTs and if you take away Outlook, they no longer have a way to access them. Microsoft does have an option to import the PSTs into the mailbox or archive mailbox (see: Using the New PST Import Service) but there is no way within OWA to access them.
No “mailto:” Functionality – If you’re used to clicking on a hyperlink to an email address on a website, in a document, etc, that functionality won’t work when you’re using OWA. In fact, the OS will likely want to launch your default email application which could be assigned as the built-in mail client.
Third Party Add-Ins – This will be come less of an issue as vendors begin to adopt the “Office Add-Ins” model that works universally with Outlook, OWA and eventually the mobile client. If you use an application today that has a client-side installation (e.g. WebEx), that functionality will be missing in OWA.


Despite the above list of differences, it doesn’t mean that OWA can’t become your primary mail client. Each user is going to have different usage requirements and different levels of tolerance to change. In many cases, the same tasks can be achieved but in a different way. Fortunately, it’s easy enough to pilot given that everyone will have access to the OWA interface as soon as they have a mailbox.
Take some time and try it yourself! Force yourself to use OWA exclusively for a week; leave a comment if you come across any other limitations.
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