The short answer to does a shared mailbox need a license is that the mailbox itself doesn’t, though some uses of it do. Microsoft’s About shared mailboxes page says a shared mailbox can store up to fifty gigabytes without a license. Each person who opens it still needs a licensed mailbox of their own. A larger size, an in-place archive or a litigation hold each need a license. So the practical task is to settle five decisions before anyone sets one up.
Those five: shared mailbox or group, whether any planned use needs a license, who gets which kind of access, how sign-in stays blocked, and who watches the size and removes people who leave. A company address created without those answers can reach its size limit. It may be opened by more people than anyone intended. It may still list someone who has left.
Does a Shared Mailbox Need a License?
Microsoft’s page says a shared mailbox can store up to fifty gigabytes without a license assigned to it. To open one, a person must have a licensed Exchange Online mailbox. The shared mailbox itself doesn’t need a separate license. So the licensing question follows the people and the use, not the address.
Some uses do need a license, and Microsoft’s About shared mailboxes page lists them. To raise the size limit to one hundred gigabytes, the page says the shared mailbox must be assigned an Exchange Online Plan 2 license. A shared mailbox with in-place archiving needs a license, and so does one placed on litigation hold. The page also says licenses might be required to apply certain advanced features. And it notes that the apps-only business plan doesn’t include email, so a shared mailbox needs a plan that does.
Treat those limits as what the page says, not as something fixed. Microsoft can change them, so confirm them on Microsoft’s page or with your IT provider before buying anything. And if the conversation drifts into which plan the business should be on, that’s a different decision from this one. A separate post on what a higher Microsoft 365 plan adds covers that ground.
Should It Be a Shared Mailbox or a Group?
Fit comes first. Microsoft’s page says only people inside your organization can use a shared mailbox. It supports a maximum of twenty-five users. And it says you can’t prevent users from deleting messages in one. For needs outside those lines, the page points to a Microsoft 365 group instead.
Make the call before anything gets created. According to Microsoft’s Create a shared mailbox page, it isn’t possible to migrate a shared mailbox to a Microsoft 365 group. So the decision belongs at the start, not after the address is in use and printed on things.
The page lists uses like company information addresses, support email addresses and reception or front-desk mailboxes. Walk through which of those the business already has, and who needs to reply from each one. Then put these three questions to your IT provider for every shared address on the list.
- Is this address for information coming in, or for replies going out?
- Does anyone outside the company need to open it?
- Would anyone need to be stopped from deleting messages in it?
Who Gets Which Kind of Access?
Each person who opens a shared mailbox still needs a licensed mailbox of their own. Beyond that, the Create page describes Full Access as letting a user open the shared mailbox and act as the owner of it. It also says a user with Full Access can’t send from it unless they also have Send As or Send on Behalf permission.
O&O Systems’ Cloud and Microsoft 365 page says it takes care of the setup and management, from selecting the licenses to configuring accounts, so your team can focus on work.
So ask who needs to read, who needs to reply and who needs both. As a general rule, access tends to get added when someone asks, and it can stay in place long after the reason for it ends. Write down who has which kind, and why. That short record is what makes the next review quick.
Why Keep Sign-In Blocked on a Shared Mailbox?
The Create page says every new shared mailbox has sign-in blocked by default. The About page says to always block sign-in for the shared mailbox account and keep it blocked. It also says the account has a system-generated password that isn’t known or intended for use.
So nobody needs a password for a company address, and nobody should be handed one. The About page says not to use that account to sign in. Staff reach the mailbox through their own sign-in instead. Ask your IT provider to confirm that sign-in is still blocked on each shared mailbox. Then ask who would notice if that ever changed.
Who Watches the Size and Removes People Who Leave?
Microsoft’s page says that when a shared mailbox reaches its storage limit, it can receive email for some time, but it can’t send. After some time it stops receiving, and senders get a non-delivery receipt. So ask who would notice, who owns the address, and who removes people who leave.
Membership in a shared mailbox can be easy to forget when someone leaves. An individual account may get closed while the company address keeps its old member list. A separate post on what to remove when someone leaves the company covers what belongs on that list.
Ask your IT provider to review who belongs to each shared mailbox on a schedule you agree on. Pick the interval together. Then keep the answer with the equipment records, where whoever asks next can find it.
What Should Your IT Provider Put in Writing?
The useful answers are the ones you can keep and check later. A shared company address can outlast the person who created it and the person who inherited it. Written answers survive that handoff. So ask these questions about each shared address, and keep what comes back.
- Is each shared address a shared mailbox or a group, and why?
- Does any planned use of it need a license?
- Who has Full Access, Send As or Send on Behalf, and who approved it?
- Is sign-in blocked on each one?
- Who watches its size?
- Who removes people when they leave, and when does that happen?
Then name one owner for each shared address on the business side. One person, not a committee. Keep the written answers with the equipment records, so the next person inherits the reasoning along with the mailbox.
Frequently Asked Questions About Shared Mailboxes
Do the people who use a shared mailbox need licenses?
Microsoft’s About shared mailboxes page says a user must have a licensed Exchange Online mailbox to access a shared mailbox. The shared mailbox itself doesn’t require a separate license. So the licenses follow the people who open it, not the address they open. If you’re unsure which staff already have one, your IT provider can confirm that for your plan.
What happens when a shared mailbox gets too big?
Microsoft’s page describes it plainly. At the storage limit, the mailbox can receive email for some time, but it can’t send. After some time it stops receiving, and senders get a non-delivery receipt. The page puts the size limit at fifty gigabytes without a license, and says a larger limit needs one. So the useful question is who watches it.
Can someone outside the company use a shared mailbox?
Microsoft’s page says only people inside your organization can use a shared mailbox. For needs it doesn’t cover, the page points to a Microsoft 365 group instead. If an outside bookkeeper or contractor has to work from a company address, that’s worth raising before the address gets created. Your IT provider can say which option fits your plan.
Can we stop staff from deleting messages in a shared mailbox?
Microsoft’s page says you can’t prevent users from deleting messages in a shared mailbox. Where restricting deletion matters, the page points to a Microsoft 365 group instead. That’s a reason to settle the shared mailbox or group question before anything gets created. Your IT provider can confirm what’s possible on the business’s plan.
Does O&O Systems help with Microsoft 365 licenses and accounts?
O&O Systems describes that work on its Cloud and Microsoft 365 page: it takes care of the setup and management, from selecting the licenses to configuring accounts, so your team can focus on work. A shared company address raises questions about both. So if the business has one, or is about to create one, raise it when getting in touch.
Decide Before the Address Goes Live
Settle the five decisions while the address is still an idea. Pick shared mailbox or group. Check whether any planned use needs a license. Decide who gets which kind of access, and remember that each person who opens it needs a licensed mailbox. Leave sign-in blocked. Name who watches the size and who removes people who leave. Then write the answers down and give each shared address one owner.
If you’re still asking does a shared mailbox need a license for your own setup, you can contact O&O Systems about the shared mailboxes in your Microsoft 365 account and start with who needs to open them.
