Hello @Te Puna Moanaroa,
Thank you for posting your query on Microsoft Q&A.
Based on your description, I understand that the "Manage" button is greyed out for your Microsoft Entra Joined device, and you're looking for information on who manages these devices.
Devices can only be managed if their mobile device management (MDM) is listed as Microsoft Intune. If the device is not enrolled in Microsoft Intune, the "Manage" option will be unavailable.
Please refer to the screenshots below from my test tenant:
Microsoft Entra Joined device not enrolled in Intune.
Microsoft Entra Joined device enrolled in Intune. For more details, you can refer to the Microsoft documentation on Manage an Intune device
Please check if your device is managed by Intune, as shown in the screenshots. If the device is not managed by Microsoft Intune, it is expected that the "Manage
" button will be greyed out.
I hope this information is helpful. Please feel free to reach out if you have any further questions.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". Thanks,
Raja Pothuraju.