Some Hybrid Azure AD joined devices get no Autopilot registration

Question

Hello,

We are testing the migration of AD joined devices, toward to Autopilot registered devices in MEM.
The devices are properly registered in the MEM as Intune managed and get a Autopilot deployment profile. There the property "Convert all targeted devices to Autopilot" is on.

But some devices aren´t registering as an Autopilot device. They have identical hardware and the same configuration.
No errors are logged in event log and status of dsregcmd on the computers and also in MEM admin center.

What could be the cause?

Thanks

edit:
Even with the devices that were registered in autopilot, not everything is OK. All of them have no "Associated Intune device".
Is the function ""Convert all targeted devices to Autopilot"" not recommendable.

Answer 1

Please note that certain Autopilot scenarios require specific minimum builds of Windows. Please make sure your device has the required minimum build of Windows 10 v1809 or greater.
Reference: https://learn.microsoft.com/en-us/mem/autopilot/windows-autopilot-hybrid#prerequisites

Also, for all of users have no "Associated Intune device", this is by design and to assign user to Autopilot manually under Window Autopilot devices:

After that, we can reset the device to process Autopilot enrollment.

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