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You can find and download Windows IoT Enterprise LTSC installation media or ISO, along with volume license keys, in the Downloads and Keys section of the Volume Licensing Service Center or the Microsoft 365 admin center. If you purchased through a volume license agreement, consult your Volume License Administrator for assistance. For product key replacement scenarios, customers must provide valid proof of purchase to be eligible for a free product key, which can be generated as per internal procedures. Otherwise, a new key must be purchased.
For more information: Windows IoT Enterprise LTSC in Volume License | Microsoft Learn
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Kate