How do I resolve an "ERROR 10009: HostID mismatch"?

The error

ERROR 10009: HostID mismatch 

indicates that the license file was generated for a machine with a different host ID. If the license file previously worked on the same machine, then something in the machine configuration has changed. Possible reasons why a HostID might change are listed in What system changes can invalidate a license file?.

If it is not possible to revert back to the computer or network interface HostID associated with your license file, then you will need a new license file.

• Commercial users: Please submit a support request via our Help Center to initiate a license transfer.
• Academic users:
  • Individual Acedemic Named-User licenses: Please refer to How do I transfer my free Individual Named-User Academic or free Online Course license?
  • Educational Institution Site floating token licenses: Please submit a support request via our Help Center to initiate a license transfer.

Further information

• How do I transfer my free Individual Named-User Academic or free Online Course license?
• How do I obtain a free academic license for a cluster or a shared computer lab?
• What system changes can invalidate a license file?
• How do I configure an AWS EC2 instance so the license file remains valid?
• How do I resolve an "ERROR 10009: License is for 8 cores, machine has XX"?