Windows 10 upgrade fails to activate

This article provides the information about "Windows 10 upgrade fails to activate due to an interruption of network connectivity during the update."

Windows 10 prompts to Activate

After installation of the Windows 10 update, a few Dell users have reported that Windows 10 has not activated.

Sometimes a low battery state may have caused an interruption of network connectivity during the upgrade.

On line activation was attempted and failed to resolve the issue.
 

Solution

Many systems have encountered a delay of 48 to 72 hours between the completion of the Windows 10 installation and the online activation completion. (This appears to be due to high volume of activation requests.) This issue is self-resolving and does not require escalation to resolve.

If the system does not activation online, then use the telephone option in the activation wizard. Microsoft was contacted, and the systems were successfully activated over the telephone. (See Microsoft reference below)
 

REFERENCE:

Microsoft - How to Activate and resolve common Product key issues in Windows 10.