Public Folder vs Shared Mailbox Differences Explained
Deciding between a public folder vs shared mailbox in Microsoft 365 can feel quite confusing. This is especially true for someone new to the O365 ecosystem. Both tools offer similar email management and collaboration features, allowing users to access shared content. However, each of them is better in niche situations.
Understanding the strengths of each of them is key for IT administrators looking to set up the right tool for their team. Don’t worry, if you lack this ability right now, you will be able to create and use both public folders and shared mailboxes effectively after you go through this write-up. I have included simple instructions that will help you decide quickly and easily.
Not only that, but through this blog post, I will help you develop insights so you can decide for yourself when it’s better to create a central inbox where people can see and respond to mail simultaneously. Moreover, we’ll also explore when it makes more sense to have a company-wide repository for documents needed by multiple team members. Let us start by understanding what exactly a Microsoft public folder means.
What is a Public Folder vs Shared Mailbox? A Digital Filing Cabinet for All
The name “Public Folder” itself reveals everything we need to know. It is a storage area that many different users can access independently.
It is not tied to any single account; rather, the organization itself is the owner. Once the admin permits, a user can add the public folder to their Outlook app and access the contents from there.
You can share emails, calendars, contacts, and even files using a public folder. The main reason organizations use a public folder is to create an archive of sorts. Information that does not change frequently is often kept inside public folders. Like for example, a company may store old project communications, departmental contacts, and training docs. A new joinee who needs to get familiar with the project can be given access to the public folder.
Moreover, public folders support a hierarchical structure, so you could store information in the following format:
Parent Public Folder (2025)
|———Q1
|———|———Apr
|———|———May
|———|———June
Making it easy to look for information when needed. Public folders are not new; they were (and still are) a facility in the on-premise Exchange Server system. Since then, Microsoft has introduced many more advanced ways to communicate and collaborate, like MS Teams, and people have been debating about public folders vs shared mailboxes. When organizations grow, the public folder architecture may not keep up, and there might be scalability issues.
Although it is possible to send emails to a mail-enabled public folder, that is not its primary use case. Instead of a two-way conversation, it is more useful as an information-sharing repository.
To fill in this gap, we have another tool that Microsoft has made available for its users, i.e., shared mailboxes. Let us learn more about it.
What is a Shared Mailbox vs a Public Folder? A Collaborative Inbox for Teams
Shared Mailbox, as the name suggests, is a special (license-free) type of Office 365 mailbox with its own email address that many different people in an organization can attach to their primary mailbox.
All those people who have the shared mailbox can then interact with it like any other regular mailbox, read messages, send mail, and everything in between. As it syncs all the activity, people can get real-time information on whether a particular email has been seen by someone else and responded to or not.
If this is your very first time interacting with Shared Mailboxes, here is a guide teaching you how to create a shared mailbox in Office 365.
You can also see how to change a public folder to a shared mailbox on your own.
Now that we have introduced both the options, let’s do a head-to-head comparison of features and see what to use when.
Public Folder vs Shared Mailbox Comparison Chart
| Feature | Public Folder | Shared Mailbox |
| Primary Purpose | Information repository and archiving for large groups. | Active email management and collaboration for a team. |
| Email Functionality | Can receive emails if mail-enabled. Not designed for sending. | Can send and receive emails from a common address. |
| User Experience | Accessed as a separate folder tree in Outlook. | Appears as a separate mailbox in a user’s Outlook profile. |
| Calendar & Contacts | It can contain calendar and contact items, but not a full-featured calendar. | Includes a fully functional shared calendar and contact list. |
| Storage Limits | Subject to organizational public folder mailbox quotas. | Up to 50 GB without a license; up to 100 GB with a license. |
| Permissions | Granular permissions (owner, editor, reviewer, etc.). | Simpler permissions (Full Access, Send As, Send on Behalf). |
| Mobile Access | Not supported on Outlook for mobile. | Fully supported on Outlook for mobile. |
As we have told you earlier, because of the collaborative requirement that both these features aim to solve, there are quite a few similarities between them as well, so check them out as well.
Similarities Between Public Folders and Shared Mailboxes
| Feature | Public Folder | Shared Mailbox |
| Multi-User Access | Can be accessed by multiple users with assigned permissions | Can be accessed by multiple users with assigned permissions |
| Shared Email Functionality | Can store emails for group access | Can send/receive emails from a common address |
| Outlook Integration | Fully integrated with Outlook desktop and web apps | Fully integrated with Outlook desktop and web apps |
| Permissions Management | Access controlled via Exchange Admin Center / PowerShell | Access controlled via Exchange Admin Center / PowerShell |
| Centralized Data | Acts as a central storage space for group information | Acts as a central inbox for group communication |
| Microsoft 365 Compliance | Data stored is subject to Microsoft 365 security and compliance policies | Data stored is subject to Microsoft 365 security and compliance policies |
| Calendars & Contacts | Can store and share calendars and contacts (if configured) | Comes with shared calendars and contacts by default |
| No Extra Licensing Cost | Included with Exchange Online and Office 365 | Typically does not require a license if under the mailbox size limit |
Conclusion
The main point of public folder vs shared mailbox boils down to one simple question: whether you want a place to keep information or a tool that multiple people can use for communication.
For archiving and pure storage use cases, there is no doubt that public folders are a superior choice. However, if you are mainly looking for a method that would facilitate multi-person email, choosing shared folders will be the right choice.
In case your organization is undergoing a migration scenario where you want to move all of the existing shared mailboxes and public folders from one Office 365 to another, look no further than the SysTools Office 365 Migration tool. It can handle the transfer of both workloads flawlessly.
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