If you are using a standalone license, try the following steps, based on CSI documentation :
To understand the fix, you have to understand the mechanism. ETABS 2016 (and its siblings SAP2000 and SAFE) relies on a sophisticated licensing system, usually managed by a company called SafeNet (now Thales) or Wibu. The software needs to "ping" the license—whether it's a USB red dongle plugged into your machine or a network license server across the office. license not recognized error 30 etabs 2016 new
The file storing your text-based license string has become corrupted or unreadable. If you are using a standalone license, try

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