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Event ID 16 — Terminal Services Client Access License (TS CAL) Availability

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Applies To: Windows Server 2008 R2

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When a client—either a user or a device—connects to a terminal server, the terminal server determines if a Terminal Services client access license (TS CAL) is needed. The terminal server then requests a TS CAL from a Terminal Services license server on behalf of the client attempting to connect to the terminal server. If an appropriate TS CAL is available from a license server, the TS CAL is issued to the client, and the client will be able to connect to the terminal server.

TS CALs are installed onto a license server by using the TS Licensing Manager tool.

Note: A terminal server running Windows Server 2008 can only communicate with a license server running Windows Server 2008.

Event Details

Product: Windows Operating System
ID: 16
Source: Microsoft-Windows-TerminalServices-Licensing
Version: 6.1
Symbolic Name: TLS_W_RETURNLICENSE
Message: The Terminal Services license server could not return an expired Terminal Services client access license (TS CAL) to the available pool of TS CALs because of following error: %1!s!.

Resolve

No further action is required

The Terminal Services license server was unable to contact another license server on the network, probably because the other license server was temporarily unavailable. The license server will try again to contact the other license server.

This is a minor warning and there is no impact to the continued functionality of the license server.

Verify

To verify that Terminal Services client access licenses (TS CALs) are installed and available on the Terminal Services license server, use the TS Licensing Manager tool.

To perform this procedure, you must have membership in the local Administrators group, or you must have been delegated the appropriate authority.

To verify that TS CALs are installed and available:

  1. On the license server, open TS Licensing Manager. To open TS Licensing Manager, click Start, point to Administrative Tools, point to Terminal Services, and then click TS Licensing Manager.
  2. If the User Account Control dialog box appears, confirm that the action it displays is what you want, and then click Continue.
  3. In the left pane, expand All Servers, and then click the license server. In the right pane, the type, version, and number of TS CALs installed on the license server is listed.

Note:  To verify that the terminal server can discover (contact) a Terminal Services license server with the appropriate type of Terminal Services client access licenses (TS CALs), use Licensing Diagnosis in the Terminal Services Configuration tool on the terminal server.

Terminal Services Client Access License (TS CAL) Availability

Terminal Services