What system changes can invalidate a license file?

Errors such as:

• ERROR 10009: HostID mismatch
• ERROR 10009: License is for 8 cores, machine has XX

indicate that the license file was generated for a machine with a different host ID, different core count, different user, etc.

Changes that can cause these errors include:

• For Windows systems: Modifying the primary disk volume ID, which can be caused by formatting or replacing the boot drive.
• For Linux and macOS: Modifying the primary network adapter; this may occur when attaching and detaching from some docking stations.
• For WSL2: The MAC address changes upon rebooting; try using WSL1. If you would prefer to use WSL2, please follow the instructions in How do I set up Gurobi in WSL2 (Windows Subsystem for Linux)?
• For AWS EC2: See How do I configure an AWS EC2 instance so the license file remains valid?
• For virtual machines (VMs): Some of these identifiers may change if you "copy" or "clone" the virtual machine instead of "moving".
• For named-user licenses: Running Gurobi under a different username.

For a HostID mismatch, see How do I resolve an "ERROR 10009: HostID mismatch"?

For a core count issue, see How do I resolve an "ERROR 10009: License is for 8 cores, machine has XX"?

Further information

• How do I transfer my free academic or free trial license to a different computer?
• How do I obtain a free academic license for a cluster or a shared computer lab?
• How do I configure an AWS EC2 instance so the license file remains valid?
• How do I resolve an "ERROR 10009: HostID mismatch"?
• How do I resolve an "ERROR 10009: License is for 8 cores, machine has XX"?