Why Does My Computer ID Keep Changing?

Updated Sep 26, 2018

Reported In


  • NI License Manager
  • LabVIEW

Operating System

  • Windows

Issue Details

  • The activation code I generated for my National Instruments software does not work.  After a restart, all my software is no longer activated.  I noticed in NI License Manager that my computer ID is not always the same. Why does my computer ID keep changing?
  • When I move my hard drive from one computer to another, LabVIEW deactivates. How can I fix this?
  • When I connect my computer to different test systems the computer ID changes and all my software is no longer activated. How can I fix this?


The computer ID is based on one of two sources: an Ethernet card's MAC address or a hard drive’s disk volume serial number. By default, desktop computers are based on an Ethernet card and laptop computers are based on a hard drive. Disabling or removing this device can lead to the computer ID changing. This will cause issues with activated National Instruments software on the system. Common examples of this situation include:
  • Switching the active Ethernet card (from wired to wireless)
  • Relabeling a hard drive (ex. changing the label from C:\ to F:\)
  • Reformatting a hard drive
Troubleshooting steps for an Ethernet card based computer ID are:

Troubleshooting steps for a hard drive based computer ID are:

Additional Information

The underlying cause of this issue is each computer can have several valid computer IDs. Each MAC address or disk volume serial number can generate a unique computer ID. Each National Instruments activation code is then based off a specific computer ID. When activating a license, the NI License Manager chooses a computer ID from all active MAC addresses (or disk volume serial numbers ). As long as these devices are present and enabled, there should be no issue. However, modifying what devices are available can cause the NI License Manager to choose a different device and subsequently generate a different computer ID.


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