OWA 2013 Offline Mode

By Nuno Mota, [Published on 14 March 2013]

Another major, major improvement [to OWA] is the introduction of Offline support, allowing users to launch OWA and start working even if there is no network connectivity! The work a user does while disconnected will then be automatically synchronized the next time the user goes online. This is very similar to Outlook Cached Mode and allows users to be productive even when they have no network connectivity.

Most e-mail and calendar actions such as sending e-mails and calendar invites, deleting e-mails, getting reminders, declining meetings, flag and categorize messages, etc. work while in offline mode. However, not every option (or action) is available, but as HTML5 evolves I reckon more and more options/actions will be made available in offline mode, bringing OWA even closer to Outlook. One example is full-text indexed search which is still not possible with OWA offline or HTML5 offline in general for that matter.

Other examples of available features and limitations of offline mode are:

  • Only the last 3 days or 150 e-mails (whichever is larger) are available and only on your Inbox, Drafts or any folder viewed within the last few days;
  • The previous month and future year of your calendar are available;
  • Only a limited set of upcoming calendar reminders are available. If you are offline for a long time, reminders will stop working until you go online so OWA can download current information;
  • All your contacts are available (this excludes contacts from social networks like LinkedIn and the Global Address List);
  • The Auto-Complete cache is available;
  • Archived folders or tasks are not available;
  • As I already mentioned, you will not be able to search or sort items when offline;
  • Built-in filters will also not work;
  • Attachments are not available.


Although offline mode is enabled for all users by default, in order to actually use it, users need to first manually enable it on each computer they want to use this feature. This is done by clicking the settings button at top right-hand corner of the main OWA page and selecting Use mail offline

Note: Offline mode has been designed for computers and laptops. It can't be enabled in browsers on smaller devices like tablets or smartphones!

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Will tablet and Smart phone use be a big part of your OWA 2013 deployment?