Q. Does remote user mailbox get created without Exchange Online license ?
Ans : Yes, It get created without Exchange Online license and would be retained for 30 days grace period. You should assign license on time to avoid any annoyance to end user or service.
Here is the test and that proves that as well.
- Created a Remote User Mailbox on-prem in a OU which is synced to Office 365.
- Verified in Azure AD Connect that new account shows in ‘Export’ activity of .onmicrosoft.com connector space and Here you can see that object with ‘Remote User Mailbox’ type is getting synced :
- After few minutes of Azure AD Sync. you will find mailbox in Office 365 and i confirmed that account had no license.
- Please make sure to assign license to such mailbox before 30 days of grace period to avoid any issue.
Thanks for reading !