When a user opens Outlook Web App in a Microsoft Office 365 environment, Outlook Web App opens only in the light version. Therefore, the user doesn't have access to the comprehensive set of features that are available in the standard version of Outlook Web App. This occurs even though the user has a web browser that supports the comprehensive feature set in the standard version of Outlook Web App.
Other users in your organization don't experience these symptoms. When other users open Outlook Web App, they have access to the comprehensive set of features that are available in Outlook Web App.
This scenario occurs if the user unintentionally selects the Use the blind and low vision experience option in Outlook Web App.
To resolve this issue, follow these steps:
Make sure that the user is using a supported web browser. For more info about the system requirements for Office 365, see Office 365 system requirements.
In Outlook Web App, click Options.
In the navigation pane on the left, click Outlook Web App version, and then clear the Use the Light Version of Outlook Web App check box.
Click Save at the top of the page.
Sign out of Outlook Web App. The next time that the user signs in to Outlook Web App, the user is presented with the standard version of Outlook Web App.
The light version of Outlook Web App is optimized to support users who are blind or who have low vision. Additionally, it supports older web browsers. For more info about the light version of Outlook Web App, see Outlook Web App Light.