Hello @PJ Tharpe
Thank you for reaching out. You can use following registry key to block Workplace join that happens with Outlook prompt "Use this account everywhere on your device" and "Allow my organization to manage my device". Basically, if end user click on "allow" the machine perform Azure Active Directory (AAD) Workplace Join.
Registry Key that can be used to block this prompt and preventing workplace join: HKLM\SOFTWARE\Policies\Microsoft\Windows\WorkplaceJoin "REG_DWORD BlockAADWorkplaceJoin=1"
I hope this answer helps to resolve your issue.
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