Sometimes, the Windows Firewall flags the license check as suspicious activity. Temporarily disable your firewall to see if ETABS launches.
ETABS is a powerhouse for structural analysis, but facing a licensing error can bring a high-priority project to a screeching halt. If you are seeing the "Unable to find a license" message in ETABS 18, it usually stems from a communication break between the software and the Sentinel RMS License Manager or an expired license file. unable to find a license etabs 18
ETABS 18 sometimes fails if it tries to launch a version (like Ultimate) that doesn't match your license (like Plus or Professional). Sometimes, the Windows Firewall flags the license check