Lync 2013: The New Lync Web App

Microsoft Lync Web App was introduced with Lync Server 2010. Lync Web App is a browser-based version of Microsoft Lync 2010, which allows users who don’t have Lync 2010 or Lync 2010 Attendee installed on their computer to participate in online meetings—even if they don’t have a Lync 2010 account. Lync Web App for Lync 2013 expands the capabilities of Lync Web App for Lync 2010. This article outlines the new features and how they compare with the earlier version.

Author: Edwin Joseph, Microsoft Senior Support Engineer

Editor: Susan S. Bradley

Technical Reviewers: Meera Krishna, Patrick Kelley, Rick Kingslan, Robert Panduru

Publication Date: January 14, 2013

Product Version: Lync 2010, Lync Web App for Lync 2010, Lync Web App for Lync 2013

Lync Web App for Lync 2010

Before we consider the new Lync Web App, let’s review the features of the Lync 2010 version.

When compared to the full Lync 2010 client, Lync Web App for Lync 2010 has a few limitations. The biggest limitation is the inability to use computer audio and video, and to upload PowerPoint presentations in meetings. Additional limitations for Lync Web App for Lync 2010 are as follows:

  • To use Lync Web App, the Microsoft Silverlight browser plug-in version 4.0 must be installed on the device. Some mobile devices do not support Silverlight.
  • Because the Microsoft Silverlight browser plug-in is not supported on 64-bit browsers, Lync Web App is not supported on 64-bit browsers. The exception is the 64-bit version of Safari running on the Macintosh operating system.
  • The desktop and application sharing feature is available to Windows users only. Users of Macintosh operating systems can view shared content but cannot initiate sharing.

NOTE   The only requirement to run Lync Web App is to install the Microsoft Silverlight browser plug-in. Silverlight installs a dedicated plugin for desktop and app sharing. Lync Web App is supported on both Windows and Macintosh operating systems.

Lync Web App for Lync 2013

The following changes have been made to Lync Web App for Lync 2013.

  • Lync Web App for Lync 2013 is a cross-browser HTML and JavaScript-based web application that doesn‘t require Microsoft Silverlight.
  • It supports both Windows and Macintosh operating systems, as did the previous version of Lync Web App.
  • It provides full Lync presentation capability, which is on par with the full-fledged desktop Lync 2013 client.
  • It supports computer audio/video and sharing, and requires an Active X plug-in to be installed.
  • It provides a simplified user interface that focuses on the meeting join experience for a guest .
  • It is available to both online and on-premises users.

Note: Because Lync Web App for Lync Server 2013 is full-featured, there is no longer a need for a Lync Attendee client.

Meeting Join Experience

When a user clicks a Lync Meeting URL, but doesn’t have the Lync 2013 desktop client installed, the user is presented with the option to join the meeting using the latest version of Lync Web App.

The new streamlined interface for Lync Web App is focused on helping the user join the meeting as a guest, as follows:

  • The options for user name and password have been removed.
  • The guest user can join the meeting immediately after entering their name, based on the meeting options—thus avoiding any confusion.
  • The expectation is that users will use VoIP and video, so the option to install the required plug-in is selected by default.
  • Users can join the meeting without installing the plug-in; however, this will limit them to view-only mode for presented PowerPoint slides during the meeting.
  • Integrated Windows Authorization (IWA) will detect credentials using Lync Web App.

Lync Web App for Lync 2013 Client Architecture

On the Lync Server 2013 Front End (for single server installations), Front End pool, and Director roles, there are two websites—internal and external. When a user accesses the Lync Web App meeting from inside the corporate network, the Lync Web App meeting is serviced from the internal website; otherwise, it is serviced from the external website. This is also true in the case of a split-DNS server. In case of a hairpin DNS—internal requests are referred by internal DNS records to the external website. The request exits the internal network and immediately turns, or hairpins, to the external entry on the reverse proxy. Lync Web App is always serviced from the external website, regardless of whether the user is inside or outside the corporate network.

Lync Web App for Lync 2013 Client Authentication

Lync Web App for Lync 2013 supports the following authentication mechanism for an online and on-premises user.

Online User

For online users, Lync Web App supports OrgID authentication, as does the rest of the Microsoft Office applications. An organization can have Office 365 accounts for a few users who get direct access. Or, an organization can turn on Active Directory Federation Services (AD FS) authentication for users who are Active Directory-based and do not have an Office 365 account.

On-Premise User

For on-premises users, Lync Web App supports the following authentication methods:

  • Forms-based authentication, where the user enters their domainusername and password in a web-based form.
  • Integrated Windows Authentication on Internet Explorer and Chrome.
  • An organization can also enable AD FS to have multi-factor authentication.

Guest login is supported in both online and on-premise modes.

Lync Web App for Lync 2013 and Reverse Proxy Support

Lync Web App for Lync 2013 supports the following scenarios:

  • Lync Web App is supported by any proxy (or reverse proxy) that supports browsers using forms-based and Integrated Windows Authentication. Additionally, the proxy must support HTML communication.
  • For media traffic (A/V and screen sharing), Lync Web App supports Kerberos, NTLM, and Digest. Basic authentication is not supported.

Lync Web App for Lync 2013 Supported Platforms

To use Lync Web App, you must have one of the supported operating system and browser combinations listed in the TechNet Library topic, Lync Web App Supported Platforms.

Lync Web App for Lync 2013 Client Troubleshooting

Here are some troubleshooting tips:

  • Always completely clear the cache and temporary files from the browser when troubleshooting Lync Web App issues.
  • To collect Lync Web App client logs:
    • Internet Explorer users running the Lync Web App plugin: Press F9 for the client logs.
    • Macintosh users: The logs are located at: userslibrarylogsLwaTracing.
    • All other users with Windows: Collect logs from: %userprofile%LWATracing.
  • If the user is experiencing issues with audio/video when using Lync web App, collect the Lync Web App MediaStack logs at %userprofile%tracingWPPMedia.
  • For http responses, such as 500 or 404, it is also useful to collect the Fiddler logs or a Strace capture.
  • To collect Lync Web App server side logs, collect enable and then collect logs for relevant scenarios using the Lync server 2013 Centralized Logging Cmdlets.
  • Centralized Logging Service scenarios can help collect relevant data for Lync Web App issues, as follows:

Scenario Name



For meeting join-related issue


For PowerPoint presentation-related issues


For desktop sharing-related issue


For Audio/video-related issues


For instant messaging & presence (SIP )-related issues

Lync 2010 and Lync Web App for Lync 2013 Issue

As of January 2013, there is a potential issue with clients using Lync 2010 and Lync Web App for Lync 2013. Lync 2010 clients might not be able to view PowerPoint content uploaded from a Lync Web App for Lync 2013 client. A fix will be available sometime in the future for the Lync 2010 client to correct this behavior.

The new Lync Web App for Lync 2013 client is a step forward in the evolution of the Lync client. The streamlined user interface makes it easy for users to seamlessly join a meeting. Plus, the new Lync Web App now delivers end users with a complete meeting experience, without the need for a client application installation.

Additional Resources

Lync Server Resources

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Comments (19)
  1. tom says:

    Lync Web App on OSX worked perfectly until recently. Now it no longer works at all! It does not detect the Plugin after installation and does not collect audio/video. Tested on Chrome current version. Tried clearing the cache, re-installing plugin – no
    difference. Can’t use it any longer.

  2. Andreas Brandmair says:

    For WindowsXP Lync Web App tracing Folder can be found in %userprofile%Local Settingsapp data Folder… LWAPlugin….

  3. Su says:

    In Lync 2013 web version, I cannot type letter ‘t’, shift ‘t’ works, I noticed few others with this issue, any fix for this issue?

  4. Hashendra says:

    Android phone cannot view Desktop or PowerPoint presentation during Meeting Now or Conference call.

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