We will proceed from simplest (no admin rights needed) to most complex (IT-level intervention).
Even if lmgrd is new, the vendor daemon (CSiBridgeDaemon.exe or similar) might be stale. ETABS 2021 looks for a specific feature signature.
Action:
Error 18 means the license file (e.g., lservrc or etabs.lic) is missing, cannot be read, or is not in the expected location. Typical causes:
ETABS License Error 18 in the 2021 version is a clear but solvable communication breakdown. It is almost never a hardware failure or a corrupt license file. Instead, it is the software's way of saying, "Your license server speaks an older language I no longer understand."
By methodically updating your license manager to version 11.16 or newer, ensuring the vendor daemon is from the 2021 package, and isolating the service if necessary, you can eliminate Error 18 permanently. Once resolved, ETABS 2021 will run reliably, allowing you to focus on structural design rather than licensing headaches.
Final Checklist for Resolution:
If you have followed all these steps and still see Error 18, the issue may be a license feature mismatch—your license file may simply not include entitlement for ETABS 2021. In that case, contact your software provider to upgrade your license plan.
This guide is intended for troubleshooting ETABS 2021. Always ensure you have a valid, legal license from Computers and Structures, Inc. or an authorized distributor. etabs license error 18 2021
ETABS License Error 18 typically indicates that a valid license code is unavailable for the requested feature. In ETABS 2021, this often stems from a mismatch between your system's locking code and the generated license file, or issues with system regional settings. Common Causes for Error 18
System Date/Number Format: The licensing tool often requires a specific date format to recognize the license properly.
Locking Code Mismatch: The machine-specific ID (HostID) used to generate the license may have changed or was incorrectly identified during setup.
Corrupted Registry Entries: Previous installations or failed updates can leave behind corrupted registry files that block new licenses. Recommended Fixes 1. Adjust Regional Settings
Many users find that changing the PC's date and number format resolves the issue. Go to Control Panel > Region. Set the format to English (United States). Ensure the date format is mm/dd/yyyy. 2. Verify Machine Locking Code
If the locking code used for your license doesn't match your actual machine code, Error 18 will persist.
Run the LicenseRequest file from the ETABS installation directory. Check the value against your license file (lservrc).
If they differ, you must regenerate the license using the correct code. 3. Perform a Clean Reinstallation We will proceed from simplest (no admin rights
Corruption in the installation folder or registry can trigger licensing errors. Uninstall all previous versions of ETABS.
Delete the Computers and Structures folder from both C:\Program Files and C:\Local App Data.
Reboot your machine and reinstall ETABS as an Administrator. 4. Network License Troubleshooting (If Applicable) If you are using a network license:
Ensure the ls host environment variable is correctly set to your server's name.
Verify that ports 80 and 443 are open on your firewall to allow communication with the license manager.
For official technical support, you can visit the CSI Knowledge Base for detailed error code resolutions.
Are you using a standalone or network license for your ETABS 2021 installation?
TECHNICAL SUPPORT REPORT
Subject: ETABS 2021 License Error 18 – Sentinel Key Not Found Date: [Current Date] Software Version: ETABS 2021 (v21.x.x) Operating System: Windows 10/11
If you are currently facing this error, here is what the official coverage recommends:
| Cause | Solution |
|-------|----------|
| Wrong license server address | Re-enter server name or IP in ETABS License Manager. |
| Firewall blocking | Add ETABS and CSI license manager executables to firewall exceptions. |
| License file corrupted | Stop license manager, replace .lic file, restart manager. |
| VPN interference | Use the VPN's local IP, or disconnect VPN for license check-out. |
| Old license manager version | Download and install the latest CSI License Manager (compatible with ETABS 2021). |
If you are using a network license, the .lic file must explicitly reference the updated daemon path.
Open your .lic file in Notepad. Look for a line like:
VENDOR CSiBridgeDaemon "C:\Program Files\CSI\License Manager\CSiBridgeDaemon.exe"
For ETABS 2021, ensure:
Since you are dealing with a 2021 version (which is no longer the latest), prevention is key: