On-prem mailbox with Online archives

[Dan Snape]

Can anyone let me know what type of user the Exchange Online user is when the users primary mailbox is on-prem (Exchange 2010) and the archive is located in Exchange Online?

At the moment we have some issues with messages not being archived, and we have some users who are mailbox users in Exchange Online, and some users who are mail contacts in Exchange Online. I would have thought that if you have an Exchange Online archive configured, then the user type would need to be a mailbox user rather than a mail contact in Exchange Online

[#2]

Are you set up with a hybrid between your Exchange Server 2010 and Exchange Online?
The Exchange Online Archiving is different for on-prem users than it is for Exchange Online users.
This article should help explain more (albeit an old one): https://technet.microsoft.com/en-us/library/hh529934(v=exchg.141).aspx

[#3]

Yes there is a hybrid setup in place. I have read that technet article, but it doesn't explain what user type the Exchange Online user is when the primary mailbox is on-premises and the archive is in Exchange Online.

[#4]

Do you actually have "Exchange Online Archiving" licenses though? Or just the usual Exchange Online / Office 365 E3/E5 licenses?

[#5]

All users have been assigned O365 E3 licenses

[#6]

As mentioned previously, "Exchange Online Archiving" is different from archiving for Exchange Online users. The naming is confusing I know.
If you want to have an archive for on-prem mailboxes, then you need that license.
Otherwise what is happening is that by assigning an E3 license you are creating a full Exchange Online mailbox - which can cause issues.
I would also suggest that you reach out to Microsoft FastTrack to help with your migration planning as they are a free resource.

[#7 · Accepted solution]

If you are in a hybrid configuration, you can assign Exchange Online Plan 2 or Exchange Online Archiving to enabling archiving features. You can assign licenses for on-premises mailboxes as well, no (online) mailbox will be created additionally. This was the case a long time ago ...

To answer your question about the recipient type in Exchange Online: it is a mail user with archive enabled. You can check it with Get-MailUser <cloud mail user> | FL *archive*

[#8]

Just to confirm this, if a customer has Office 365 E3 or E5, they have hybrid enabled but no mailboxes migrated, and simply want Exchange Online Archiving with their On-Prem Exchange 2010 mailboxes for now, they can utilize their existing Exchange Online (Plan 2) Sub-SKUs and not have to purchase the specific Exchange Online Archiving license?

[#9]

Yes you can. The E3 and E5 licenses both include Exchange Online (Plan 2) as a service, which allows you to use Exchange Online Archiving.