When people chat in Microsoft Teams (MS Teams), a ‘compliance’ copy of the chat is saved to either personal or (Microsoft 365) Group mailboxes. This copy is subject to retention policies, and can be found and exported via Content Search.
But what happens if there is no Exchange Online mailbox? It seems the chats become inaccessible which could be an issue from a recordkeeping and compliance point of view.
This post explains what happens, and why it may not be a good idea (from a compliance and recordkeeping point of view) not to disable the Exchange Online mailbox option as part of licence provisioning.
Licences and Exchange Online mailboxes
When an end-user is allocated a licence for Microsoft 365, a decision (sometimes incorporated into a script) is made about which of the purchased licences – and apps in those licences – will be assigned to that person.
E1, E3 and E5 licences include ‘Exchange Online’ as an option under ‘Apps’. This option is checked by default (along with many of the other options), but it can be disabled (as shown below).
If the checkbox option is disabled as part of the licence assigning process (not after), the end-user won’t have an Exchange mailbox and so won’t see the Outlook option when they log on to office.com portal. (Note – If they have an on-premise mailbox, that will continue to exist, nothing changes).
Having an Exchange Online mailbox is important if end-users are using MS Teams, because the ‘compliance’ copy of 1:1 chat messages in MS Teams are stored in a hidden folder (/Conversation History/Team Chat) in the Exchange Online mailbox of every participant in the chat. If the mailbox doesn’t exist, those copies aren’t made and so aren’t accessible and may be deleted.
If end-users chat with other end-users who don’t have an Exchange mailbox as shown in the example below, the same thing happen – no compliance copy is kept. The chat remains inaccessible (unless the Global Admins take over the account).
The exchange above, between Roger Bond and Charles, includes some specific key words. As we will see below, these chats cannot be found via a Content Search.
(On a related note, if the ability to create private channels is enabled and they create a private channel and chat there, the chats are also not saved because a compliance copy of private channel chats are stored in the mailboxes of the individual participants.)
Searching for chats when no mailbox exists
As we can see above, the word ‘mosquito’ was contained in the chat messages between Roger and Charles.
Content Searches are carried out via the Compliance portal and are more or less the same as eDiscovery searches in that they are created as cases.
From the Content Search option, a new search is created by clicking on ‘+New Search’, as shown below. The word ‘mosquito’ has been added as a keyword.
We then need to determine where the search will look. In this case the search will look through all the options shown below, including all mailboxes and Teams messages.
When the search was run, the results area shows the words ‘No results found’.
Clicking on ‘Status details’ in the search results, the following information is displayed – ‘0 items’ found. The ‘5 unindexed items’ is unrelated to this search and simply indicates that there are 5 unindexed items.
Double-checking the results
To confirm the results were accurate, another search was conducted where the end-user originally did not have a mailbox, and then was assigned one.
If the end-user didn’t have a mailbox but the other recipient/s of the message did, the Content Search found one copy of the chat message in the mailbox of the other participants. Only one item was found.
When the Exchange Online option was enabled for the end-user who previously did not have a mailbox (so they were now assigned a mailbox), a copy of the chat was found in the mailbox of both participants, as shown in the details below (‘2 items’).
Summary and implications
In summary:
- If end users chat in the 1:1 area of MS Teams and don’t have an Exchange Online mailbox, no compliance copy of the chat will be saved, and so it will not be found via Content Search.
- If any of the participants in the 1:1 chat have an Exchange Online mailbox, the chat will appear in the mailboxes of those participants.
- If all participants in the 1:1 chat have an Exchange Online mailbox, the chat will be found in the mailbox of all participants.
Further to the above:
- If end users can delete chats (via Teams policies) and don’t have a mailbox, no copy of the chat will exist.
- If end-users with a mailbox can delete Teams chats, but a retention policy has been applied to the chats, the chats will be retained as per the retention policy (in a hidden folder).
And finally, if you allow private channels, end-users can create private channels in the Organisation Team. The chats in these private channels are usually stored in the personal mailboxes of participants (not the Group mailbox) – so these chats will also be inaccessible and cannot be found via Content Search.
The implications for the above are that, if you need to ensure that personal chat messages can be accessed (from Content Search), then the participants in the chat must have an Exchange Online mailbox.
Further, if you allow deletion of chats but need to be able to recover them for compliance purposes, a retention policy should be applied to Teams 1:1 chat.
Records about the world 
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