Finding a "free" registry key for Remote Desktop Services (RDS) Client Access Licenses (CALs) is a common search for IT admins facing budget constraints or lab setups. However, the reality of RDS licensing is more about compliance than simple registry hacks. The 120-Day Grace Period
Microsoft provides a built-in window to test RDS without purchasing licenses. Duration: 120 days. Function: Full RDS functionality for users/devices.
Resetting: Possible in lab environments by deleting the GracePeriod registry subkey.
Location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod. Why "Free Registry Keys" Don't Exist
Unlike legacy software, modern RDS CALs are not unlocked by a simple alphanumeric string hidden in the registry.
Server-Side Validation: CALs are installed via the RD Licensing Manager.
Clearinghouse Connect: The server must validate with Microsoft's clearinghouse.
Digital Certificates: Licenses are issued as digital certificates, not plain text keys.
Database Entry: Installed CALs are stored in an encrypted database (C:\Windows\System32\LServer). Common Myths vs. Reality "I found a key online" Likely a volume license key that will be blacklisted. "Registry hacks bypass activation"
Hacks only reset the timer; they don't "activate" the server. "I don't need CALs for 2 users" True for administrative RDP, but not for RDS Role features. Legitimate Ways to Get RDS CALs
If you are operating a business, avoid "free key" sites which often distribute malware or pirated VLK data.
Microsoft Action Pack: Affordable for small IT partners/devs.
Visual Studio Subscriptions: Includes RDS for testing and development.
CSP/SPLAs: Pay-as-you-go monthly licensing for service providers. 💡 Key Takeaway
Resetting the grace period key is a temporary fix for troubleshooting or dev labs. For production, there is no "secret key" to bypass the Licensing Manager. Using unauthorized keys puts your infrastructure at risk of audit penalties and security breaches. If you'd like to dive deeper into the technical setup: Step-by-step guide to resetting the 120-day grace period Comparison between User CALs and Device CALs rds cal license registry key free
Troubleshooting "No Remote Desktop License Servers Available" errors Which of these should we tackle next?
Unlocking Testing Environments: Managing the RDS Grace Period
When setting up a Remote Desktop Services (RDS) environment, Windows Server provides a 120-day grace period to allow for configuration and testing before requiring permanent Client Access Licenses (CALs). For lab or non-production environments, administrators sometimes need to manage or reset this period via the Windows Registry. 1. Locate the RDS Grace Period Key
The "time bomb" that tracks your trial period is stored in a specific registry subkey on the session host.
Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod
Key Value: Look for a REG_BINARY entry typically starting with L$RTMTIMEBOMB. 2. Take Ownership and Reset
By default, even administrators cannot modify this key. To reset the countdown back to 120 days for testing purposes:
Change Permissions: Right-click the GracePeriod folder, select Permissions, then Advanced.
Change Owner: Change the owner to the local Administrators group.
Grant Control: Check Replace owner on subcontainers and grant the Administrators group Full Control.
Delete Entry: Delete the L$RTMTIMEBOMB value and reboot the server. Upon restart, Windows will generate a fresh 120-day timer. 3. Configure Licensing Mode Manually
If you have already installed a License Server but need to force the mode (Per User vs. Per Device) through the registry, use these paths: Guidance for troubleshooting RDS Licensing - Windows Server
There is a licensing grace period of 120 Days during which no license server is required. Microsoft Learn How to Configure Remote Desktop Licensing Mode - TSplus
Steps to Configure Licensing Mode using the Registry Navigate to Licensing Key: Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ Finding a "free" registry key for Remote Desktop
Managing Remote Desktop Services (RDS) through the registry is often necessary for troubleshooting license errors or resetting the 120-day evaluation period. 🛡️ Resetting the 120-Day Grace Period
When the initial 120-day RDS grace period expires, you can manually reset it by removing the "TimeBomb" registry key. This is typically done in non-production environments to extend testing. Registry Path
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod Steps to Reset Open Regedit: Run regedit.exe as an administrator.
Take Ownership: Right-click the GracePeriod folder → Permissions → Advanced. Change the owner to Administrators and check "Replace owner on subcontainers".
Grant Access: Give the Administrators group Full Control permissions.
Delete Key: Find the binary entry starting with L$RTMTIMEBOMB and delete it. Reboot: Restart the server to renew the 120-day countdown. ⚙️ Configuring RDS Licensing Mode
If your server reports that the "Licensing mode is not configured," you can force these settings via the registry instead of using Group Policy. Licensing Mode Key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\Licensing Core
The following write-up covers the standard procedures for managing Remote Desktop Services (RDS) Client Access Licenses (CALs), focusing on registry-based configuration and temporary resets of the 120-day grace period. 1. RDS CAL Configuration via Registry
Configure licensing modes and servers via the registry, ideal for non-GPO environments. Microsoft Learn Licensing Mode: LicensingMode (DWORD) in ...\RCM\Licensing Core (Per Device) or (Per User). License Server: Add the server IP/name under ...\RCM\LicenseServers Workgroup Auth: DisableWorkgroupAuthEnforcement (DWORD) to ...\Services\TermServLicensing\Parameters Microsoft Learn 2. Resetting the 120-Day Grace Period To extend access, you can delete the "timebomb" key. Navigate to ...\Control\Terminal Server\RCM\GracePeriod
Take ownership of the key and grant full control to Administrators. Delete the binary value starting with L$RTMTIMEBOMB Reboot the server to reset the countdown. 3. Activating Official CALs Remote Desktop Licensing Manager for official license installation.
While there is no legal "free" registry key to permanently license Remote Desktop Services (RDS), you can use the registry to reset the 120-day grace period or manually configure your licensing mode. 1. Resetting the 120-Day Grace Period
For testing, you can reset the "timebomb" registry key to renew the 120-day period. Open Registry Editor (regedit) as Administrator.
Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod. RDS CALs : These are required for each
Take Ownership: Right-click, select Permissions > Advanced, and change the Owner to "Administrators," ensuring full control is granted. Delete Key: Delete the L$RTMTIMEBOMB entry. Reboot the server. 2. Manual Licensing Configuration via Registry
If you have valid CALs, you can manually configure settings at HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\Licensing Core: LicensingMode: Set to 2 (Per Device) or 4 (Per User).
LicenseServers: Specify the server IP/FQDN in ...\RCM\LicenseServers. 3. Official Activation (Proper Method) For production, use the RD Licensing Manager:
Install Role: Use Server Manager to add "Remote Desktop Licensing".
Activate Server: In Licensing Manager, right-click and "Activate Server," or use the Microsoft activation website.
Install CALs: Add your licenses (Open Value/SPLA) via the wizard.
RDS CALs: These are required for each user or device that accesses a Remote Desktop Session Host (RD Session Host) server. There are two types of CALs: Per Device and Per User. The Per Device CAL is assigned to a device, and the Per User CAL is assigned to a user.
License Registry: In the context of RDS, licensing information is typically managed through the Remote Desktop Licensing server. This server issues RDS CALs to clients.
Free or Trial Keys: Microsoft occasionally offers free or trial keys for products and services, including RDS CALs, for testing or limited use. However, using a "free" registry key found through a search might not be legitimate or could pose security risks.
| Purpose | Registry Path |
|---------|----------------|
| RDS Licensing mode | HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\LicensingCore |
| License server configuration | HKLM\SYSTEM\CurrentControlSet\Services\TermService\Parameters\LicenseServer |
| Grace period status | HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod |
In a non-production environment, Windows Server allows an unlicensed RDS grace period of 120 days (extendable to 240 days with commands). This is the only “free” period built into the system.
You can reset the grace period using this command (for lab testing only):
reg delete "HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod" /f
After a reboot, the grace period restarts — but this is not a permanent license, and Microsoft does not support it for production.
If you have 5 users, buy them Windows 10/11 Pro workstations. Windows Pro allows 1 remote session natively (Remote Desktop). Combined with Quick Assist or a free VPN, you avoid the RDS CAL ecosystem entirely.
If you purchased User CALs but the server is set to Device mode, edit this DWORD:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCMLicensingMode
2 = Per Device4 = Per User5 = Not configured (Grace period)