ERROR 10009: HostID mismatch Sonja Mars January 11, 2021 21:43 Updated Follow We discuss this error and its resolution in detail in How do I resolve an "ERROR 10009: HostID mismatch"? Related articles What system changes can invalidate a license file? How do I resolve an "ERROR 10009: HostID mismatch"? How do I transfer my free academic or free trial license to a different computer? ERROR 10009: License is for 8 cores, machine has xx How does Gurobi count cores?