Rds Cal License Registry Key May 2026

Symptom: RDS session host shows “Per User” mode, but users get a temporary license expiration warning.
Check:

Cause: Per User CALs are not auto-applied — they require tracking in AD or manual installation. Registry only stores the mode preference.
Fix: Ensure Per User CALs are actually installed on the license server (RD Licensing Manager → Install Licenses).

Each Windows client stores its issued RDS CAL locally to avoid re‑requesting it:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSLicensing

Subkeys:

Use case: If a client cannot connect due to “no license available” but should have one, delete the MSLicensing key (after backup) and reconnect.

When you decommission an old license server, your RDS host may still attempt to contact it. Removing the server’s entry from SpecifiedLicenseServers forces the host to fail over to another server.

| Aspect | Rating | Notes | |--------|--------|-------| | Usefulness for admins | ⭐⭐⭐⭐☆ | Critical for troubleshooting & recovery | | Safety for manual editing | ⭐☆☆☆☆ | Dangerous except for LicensingMode / LicenseServers | | Documentation clarity | ⭐⭐☆☆☆ | Microsoft docs are sparse on per-user CAL registry details | | Recommended approach | Avoid direct edits | Use Server Manager or Group Policy |

Final recommendation: The RDS CAL registry key is a powerful but risky diagnostic tool. Only modify LicensingMode and LicenseServers when group policy cannot be applied. Never touch the IssuedLicenses subtree without Microsoft Support involvement.

When you configure an RDS session host to use a specific license server (either manually or via Group Policy), the server saves that information here:

Example (PowerShell view):

Path: HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\SpecifiedLicenseServers
Value: "LS1.domain.local" "LS2.domain.local"

Remote Desktop Licensing (RD Licensing) manages the issuance of CALs. When a device connects to an RD Session Host, the License Server issues a temporary or permanent CAL. This license is cryptographically bound to the hardware ID of the device.

Microsoft does not document these registry keys in the Windows UI; they are stored in binary format and encrypted. Direct manipulation of these keys is unsupported and can lead to licensing failures.