unity报错出现Asset database transaction committed twice!

错误描述：
运行时报错

• Assertion failed on expression: ‘m_ErrorCode == MDB_MAP_RESIZED || !HasAbortingErrors()’
• Asset database transaction committed twice!
• Assertion failed on expression: ‘errors == MDB_SUCCESS || errors == MDB_NOTFOUND’

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解决办法：
保存文件，重新打开unity或激活许可证

原因：
资源丢失造成的错误，或许可证到期。