that start with adskflex or CSIflex (be cautious not to delete other vendor files). Restart ETABS and activate the license again.

Simple but often overlooked. If your Windows date/time is wrong, the license will not validate. your computer time with an internet time server. Restart ETABS. Summary Table of Solutions

: If using a USB key or standalone CID, ensure the Sentinel System Driver is installed and functioning. You can reinstall it from the KeyDriver folder in your installation directory. Clean Re-registration