Running the client as an administrator on the first subsequent connection is mandatory. It grants the Remote Desktop client the necessary permissions to recreate the deleted registry keys and successfully request a fresh, valid token from the license server. 2. Terminal Server Client Settings (Host-Side)
If no CAL exists, the Session Host requests a temporary or permanent CAL from the RDS Licensing Server on behalf of the client.
Upon reboot, the server will recreate a fresh 120-day grace period timer.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod . rds cal license registry key
Underneath this key, you will typically find two critical subkeys:
If you need to wipe all installed licenses (e.g., for troubleshooting or moving to a new server):
This error can occur when attempting to install RDS CALs, particularly with Open Value agreements. If the registry key appears empty, converting the license to a Retail License (via Microsoft Volume Licensing support) often resolves the issue. Running the client as an administrator on the
In the fluorescent-lit hum of the Server Room, a junior admin named Leo stared at a flickering monitor. It was 4:45 PM on a Friday. He was trying to get a new Remote Desktop Session (RDS) host online, but every user who tried to log in was met with a cold, digital wall: “The remote session was disconnected because there are no Remote Desktop License Servers available.”
Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\Licensing Core" -Name "LicensingMode" -Value 4 Use code with caution. Specifying the Licensing Server Address powershell
In a perfect world, you would never touch these registry keys. However, real-world troubleshooting often forces an administrator’s hand. Common scenarios include: Terminal Server Client Settings (Host-Side) If no CAL
For production, Microsoft recommends using official tools over direct registry edits:
When the CAL Usage Report shows no installed or issued CALs, double-check that the license server is correctly activated and that the correct license program and agreement numbers were used during CAL installation. Sometimes, selecting the wrong license program (e.g., Open Value vs. Retail) causes installation failures.
When you install the RD Session Host role, Microsoft grants a 120-day licensing grace period. The system tracks this countdown via a secured registry key:
# List installed license packs Get-WmiObject -Class Win32_TSIssuedLicense -Namespace root\cimv2\terminalservices
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod Target Entry : A binary entry starting with L$RTMTIMEBOMB Steps to Reset Take Ownership : Right-click the GracePeriod folder, select Permissions , and change the to the local "Administrators" group. Grant Permissions Full Control to the "Administrators" group. Delete Key : Right-click the