Hello @CatieAdams-0084,
Thank you for posting your query on Microsoft Q&A.
Based on your question, I understand that you want to know whether if you change the setting, "Users may join devices to Microsoft Entra" from "all" to "selected" does this do anything with the devices that were joined before this setting was changed?
Please note that after changing the setting from "Users may join devices to Microsoft Entra" from "all" to "selected", it will not cause any impact to the devices which are already Microsoft Entra joined as this setting is specific to the individual users whether they can join their devices to Microsoft Entra ID and it will not cause any issues to the devices which are already successfully joined to Microsoft Entra ID before this setting was changed.
- If All is selected, all users can join their devices to Microsoft Entra ID.
- If Some is selected, only users specified under Selected can join their devices to Microsoft Entra ID.
Note
This step of allowing users to join devices to Microsoft Entra ID is only needed for the Windows Autopilot scenarios involving Microsoft Entra join. This setting doesn't apply to Windows Autopilot scenarios involving Microsoft Entra hybrid join.
For additional details, please refer to the below document for your reference.
I hope this above information provided is helpful. Please feel free to reach out if you have any further questions.
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