Microsoft Outlook is an email and personal information manager software primarily used in professional settings.

As part of the Microsoft Office suite, it offers email management, contact storage, calendar scheduling, and task tracking.

Outlook can function independently or as part of a larger Microsoft ecosystem, including integration with SharePoint for file sharing.

While it stores email data locally for offline access, newer versions restrict link opening to Microsoft's own browsers.

[15][13]Privacy is severely degraded in latest versions, as new Outlook sends passwords, mails and other data to Microsoft.

Outlook 2011 initially supported Mac OS X's Sync Services only for contacts, not events, tasks or notes.

[42] A UserVoice post created in December 2019 suggesting that the missing functionality be added has shown a "Planned" tag since October 2020.

[44] First released in April 2014 by the venture capital-backed startup Acompli, the company was acquired by Microsoft in December 2014.

[48][49] Similar to its desktop counterpart, Outlook mobile offers an aggregation of attachments and files stored on cloud storage platforms; a "focused inbox" highlights messages from frequent contacts, and calendar events, files, and locations can be embedded in messages without switching apps.

The app supports a number of email platforms and services, including Outlook.com, Microsoft Exchange and Google Workspace (formerly G Suite) among others.

[55] Outlook mobile supports a large number of different e-mail services and platforms, including Exchange, iCloud, Gmail, Google Workspace (formerly G Suite), Outlook.com, and Yahoo!

Outlook mobile temporarily stores and indexes user data (including email, attachments, calendar information, and contacts), along with login credentials,[64] in a "secure" form on Microsoft Azure servers located in the United States.

Concerns surrounding these security issues have prompted some firms, including the European Parliament, to block the app on their Exchange servers.

[66][67][68] Microsoft maintains a separate, pre-existing Outlook Web Access app for Android and iOS.

The app lets users create groups, mention their contacts, share Office documents via OneDrive and work on them together, and participate in an email conversation.

[70] Outlook Groups was updated on September 30, 2015, that introduced a deep linking feature as well as fixing a bug that blocked the "send" button from working.

[citation needed] In March 2016 Microsoft added the ability to attach multiple images, and the most recently used document to group messages as well as the option to delete conversations within the application programme.

This meant that HTML and Cascading Style Sheets (CSS) items not handled by Word were no longer supported.

[77] Outlook and Exchange Server internally handle messages, appointments, and items as objects in a data model which is derived from the old proprietary Microsoft Mail system, the Rich Text Format from Microsoft Word and the complex OLE general data model.

Outlook does not fully support data and syncing specifications for calendaring and contacts, such as iCalendar, CalDAV, SyncML, and vCard 3.0.

Among the most publicized security features are that Office Outlook 2003 does not automatically load images in HTML emails or permit opening executable attachments by default, and includes a built-in Junk Mail filter.

The term also refers to programs where the main function is to work on Outlook files, such as synchronization or backup utilities.

[86] SalesforceIQ works from inside the Outlook inbox providing data from CRM, email, and customer social profiles.

Outlook 2013 later integrated the functionality of this add-in and added the ability to import email (as well as a calendar) through Exchange ActiveSync protocol.

[99][100][101] The new Outlook has been criticized for having worse performance compared to the previous native versions as well as lack of offline support and missing a unified inbox.