Our company upgraded its client machines to Windows 2000 Professional, and we decided to upgrade from Windows NT Server 4.0, Terminal Server Edition (TSE) to Win2K Server Terminal Services at the same time. Now, however, when some users try to access the terminal server from Win2K Pro machines, they can't connect. According to the Event Viewer, the temporary licenses have expired. I didn't think that Win2K Pro clients needed terminal services client access licenses (TSCALs). What am I missing, and how do I fix this problem?
Win2K Pro clients have TSCALs built-in. Nevertheless, if you don't have a Terminal Services licensing server set up and registered on your network, your Win2K Pro clients might still experience the problems you described. The first time the clients connect, they grab 90-day temporary licenses. The next time they connect, they try to upgrade those temporary licenses to full TSCALs. Consult the Terminal Services licensing tool to see what licenses your terminal server has issued.
To fix the problem, you must edit the registry to clear the temporary licenses from your Win2K Pro clients. (If you're not working with Win2K Pro clients, be careful when deleting licenses—if you delete a valid TSCAL, you'll have a hard time replacing it.) Start a registry editor (I recommend regedit.exe because you can analyze registry values more closely than you can with regedt32.exe). Open the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSLicensing\Store\, and look for a subkey or subkeys called LICENSExxx (e.g., License002). The LICENSExxx subkey contains four values, ClientLicense, CompanyName, LicenseScope, and ProductID, which you can examine to identify the subkey that contains the temporary license information. Once you have identified the temporary license's subkey, right-click that LICENSExxx subkey and delete it. The client machine should now be able to connect to the terminal server without any problems. Make sure that your licenses server is configured correctly and that it issues proper licenses to your clients. Then, everything should work out well.
For more information, see Christa Anderson’s Microsoft Offers TSCAL Licensing Fix. If your problem persists, consult Microsoft Support. Good luck.