Removing Terminal Server licenses from an RDP client (187614)

Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SUMMARY

If an unlicensed client connects to a Terminal Server for the first time, the Terminal Server issues the client a temporary Terminal Server Client Access License (CAL) token. After the user has logged into the session, the Terminal Server instructs the License Server to mark the issued temporary Terminal Server CAL token as being validated. The next time the client connects, an attempt is made to upgrade the validated temporary Terminal Server CAL token to a full Terminal Server CAL token. If no license tokens are available, the temporary Terminal Server CAL token will continue to function for 90 days. The license is stored in the client's registry.

Thirty-two bit RDP clients store their license under the key HKEY_LOCAL_MACHINE\Software\Microsoft\MSLicensing.

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To clean the client's license cache, just delete this key and its subkeys. The next time the client connects to the server, it will obtain another license.

For 16-bit RDP clients, run regedit /v. Then delete the keys under "\Software\Microsoft\MSLicensing" to clean the client's license cache. You can also delete the BIN files from \Windows\System\Regdata.

The RDP client for Macintosh stores the license in a file on the local computer in the folder hierarchy under /users/Shared/Microsoft/RDC Crucial Server Information/. To clean the Macintosh client's license cache, delete the contents of this folder. The client will try to obtain a new license from the server the next time that it connects.