Add an exception for the Sentinel RMS License Manager executable ( lservnt.exe ).

Changes in network adapters, MAC addresses, or hardware components can invalidate a standalone license lock.

Error 120 specifically indicates an incomplete license file, meaning the necessary licensing data for ETABS to verify your right to use the software is missing or damaged.

If your IT team is familiar with FlexNet licensing, the fix takes minutes. For individual users or small firms without dedicated IT support, the error can cause significant downtime. Recommendation: Before purchasing ETABS, ensure your IT environment is prepared to maintain a CSI License Manager server, or opt for the standalone USB license to avoid network-related error 120 entirely.

The typically indicates that the license file is incomplete . This error often occurs when a license has been updated but the local machine fails to recognize the new parameters, or if the license activation process was interrupted. Primary Solutions

The log file CSI_SentinelLM.log (found in the application data directory) is a valuable diagnostic tool. Examine it for specific error codes or messages around the time Error 120 occurred to pinpoint issues with server access or corrupted license files.

Delete any existing text and type the or Host Name of the license server. If you are using a standalone license, type localhost . Save the file and restart ETABS. Verify the Sentinel RMS License Manager