Client-Side Logging and Diagnostics


Topic Last Modified: 2012-10-18

This topic describes how to use logging tools, Event Viewer, the Microsoft online services diagnostic and logging (MOSDAL) support toolkit, and the Microsoft Lync 2010 configuration information window to gather information that you can provide to the second-level support team for help troubleshooting Lync 2010.

Logging Tools

Client-side logging collects information that the second-level support team can use to determine the cause of an issue. There are four types of log files that are most useful for troubleshooting issues with Lync:

  • Client logs   Document the behavior of Lync, and add diagnostic messages to Windows event trace log (ETL) files.

  • Unified Communications Client Platform (UCCP) logs   Track server connection issues.

  • Windows ETL files   Record significant events on a computer, such as when a user logs on or when a program encounters an error.

  • Media logs   Record the status of audio and video connections.

Enable Lync client-side logging by doing the following:

  1. In the upper right corner of the Lync main window, click Options (gear icon).

  2. In the Lync - Options dialog box, click General.

  3. Under Logging, select the Turn on logging in Lync and Turn on Windows Event logging for Lync check boxes.

  4. Click OK.

  5. Restart Lync, and then try to reproduce the issue. 

The file Communicator-uccp.log is created in the directory username\tracing.  Also, Lync writes the following types of errors to the Windows ETL files, along with detailed troubleshooting information:

  • Errors that prevent a user from logging on to the server, such as host or domain name errors or a valid certificate that is not valid

  • Diagnostic messages returned by the server, such as version check failures, problems with log-in credentials, or errors generated in response to a SIP INVITE message from the client

Windows ETL files are typically created on your computer in the username\tracing folder and enable administrators and Microsoft support technicians to troubleshoot problems.

For media logs, if the Collect Logs button is enabled in the Lync UI, you can use it to help troubleshoot audio and video quality issues by doing the following:

  1. In the Lync main window, click Collect Logs.

  2. In the Collect Logs dialog box, in the Select issue type list, click the issue category.

  3. If the Select issue details list is available, click the issue subcategory.

  4. (Optional) In the text box, type an additional descriptive detail.

  5. If you see a notification about poor audio or video quality, click Yes.

  6. (Optional) To archive the final 30 seconds of the last call, select the Include a sample voice recording of your latest call check box.

  7. (Optional) To have Lync capture the desktop, select the Include a screenshot of your desktop (highly recommended) check box.

  8. Click OK.

The media log (.cab) files will be gathered up and stored in the userprofile\tracing folder and can be sent to your Microsoft support team. If you are having repeated problems with audio or video calls, you can ask your users to create a new .cab file any time they encounter a problem.

Event Viewer

Use Event Viewer to get details about a specific error message, and then search Microsoft TechNet or Microsoft Help and Support for the error and event ID. Event Viewer does the following:

  • Provides basic single-computer health monitoring and data for troubleshooting scenarios

  • Displays event logs available on the system

  • Enables troubleshooters to browse, filter, and navigate events to determine what is not working on the system and to help determine the cause of an issue and how to fix it

Before using Event Viewer, ensure that Windows Event logging for Lync is enabled by clicking Options from the Lync main window, clicking General, and then looking under Logging.

For details about Event Viewer, see the following (as applicable):

MOSDAL Support Toolkit

The MOSDAL support toolkit collects system configuration, network configuration, and service-based programs' configuration and logging data, along with performing network diagnostics. For details, see Microsoft Knowledge Base article 960625, “The Microsoft Online Services Diagnostics and Logging (MOSDAL) support toolkit” at

To enable MOSDAL logging, do the following:

  1. Download and install “MOSDAL (Microsoft Online Services Diagnostics and Logging) Support Toolkit” from the Microsoft Download Center at

  2. Enable Verbose Logging: Click Start, click All Programs, click MOSDAL, click Enable-Disable Verbose Logging, and then click Office Communicator.

  3. Run MOSDAL Toolkit: Click Start, click All Programs, click MOSDAL, and then click MOSDAL Support Toolkit.


To enable tracing in Windows Vista, you must add the user to the Performance Log Users group. After the user is added, he or she must log off and then log back on for the setting to take effect.

Lync 2010 Configuration Information Window

Configuration information is available in client-side logs and the registry. It is also available in the Lync configuration information window, where it is easier to read.

To open the Lync configuration information window, press Ctrl and click the Lync icon in the Windows notification area, and then click Configuration Information.

The values listed in this window are retrieved during logon by in-band provisioning from the server or set by Group Policy. In-band provisioning involves configuration information sent from a server to a client program.

The following configuration information is important to collect when gathering information to troubleshoot Lync issues:

  • Server SIP URI   Specifies the server, port, and mode (Transmission Control Protocol [TCP] or Transport Layer Security [TLS]) that the client is currently connected to.

  • MAPI Information   Specifies the status of the Microsoft Exchange Server mailbox integration.

  • MRAS Server   Specifies whether the user has valid credentials for the A/V. Edge Server

  • GAL Status   Specifies the address used to download the address book.

  • URL Internal from Server   Specifies the URL used for the address book download.

  • URL External from Server   Specifies the URL used to expand distribution groups.

  • Inside User Status   Specifies whether the user is connected to the internal Microsoft Lync Server 2010 or the Edge Server.

  • SIP Server URI   Specifies whether the user is connected by using TLS or TCP.

See Also


Monitoring Server Reports