Understanding shared mailboxes in Microsoft 365: The benefits and best practices

28 July 2025

Shared mailboxes in Microsoft 365 are a powerful tool for teams that need to manage emails collaboratively. Whether it’s a generic address like hello@yourorganisation.co.uk, servicedesk@, or support@, shared mailboxes allow multiple users to read and respond to messages from a common mailbox. They’re included free with most Microsoft 365 plans, making them an efficient and cost-effective solution for many organisations. 

What is a shared mailbox? 

A shared mailbox is a mailbox that doesn’t have a dedicated username or password. Instead, it’s accessed by users who have been granted permissions to it. Once added, team members can send and receive emails from the shared address and carry out other mailbox activities such as organising emails into folders and checking flagged items for follow-up. 

Shared mailboxes are commonly used for: 

  • Customer service or helpdesk teams 
  • Generic company email addresses (e.g. hello@yourorganisation.co.uk) 
  • Departmental communication (e.g. hr@, finance@, sales@) 

The benefits of using shared mailboxes 

  1. Centralised communication
 
    Shared mailboxes provide a single point of contact for external or internal queries, making it easier to manage communication within departments or customer-facing roles. 
  1. No additional login required 
    You don’t log in directly to a shared mailbox using a separate username and password. Access is always delegated from an existing M365 account making access to the mailbox quick and easy. 
  1. No additional licensing 
    Unlike user mailboxes, shared mailboxes don’t require a separate Microsoft 365 license – unless they exceed 50GB in size, making them a cost-effective solution. 
  1. Better collaboration 
    Multiple users can read and reply to emails, with the ability to see what’s been handled and what hasn’t, reducing duplication and improving team efficiency. 
  1. Shared calendar access 
    Shared mailboxes also include a shared calendar, allowing teams to schedule meetings or log events related to the mailbox’s function. 
  1. Consistent branding 
    Teams can respond to emails from a unified address, presenting replies consistently from only one address, to clients or external contacts. 
  1. Adaptability 
    Shared mailboxes can be converted to a regular mailbox at any time, and vice versa. Converting to a shared mailbox could be useful as a temporary solution if a staff member is going on long-term leave, but are expected to return at a later date – saving money on the licence and allowing easy access if the email account still needs monitoring. 

The drawbacks and limitations 

While shared mailboxes offer a lot of value, they do have some minor limitations: 

  1. License requirements over 50GB 
    If your shared mailbox grows beyond 50GB, you’ll need to assign a license to it, or archive emails to reduce size. 
  1. Limited functionality 
    Compated to ordinary mailboxes, shared mailboxes lack many features available to personal accounts, such as advanced rules and signature management. 

Shared mailbox vs. Microsoft 365 group vs. email alias 

Microsoft 365 group 
Provides a shared mailbox, calendar, Planner, files (via SharePoint) and Teams Channels. More than just email, it’s a full collaboration suite. Members receive emails in their own inbox rather than a shared mailbox and can collaborate using other Microsoft 365 tools. 

Alias 
An alias is simply an additional email address for an existing mailbox. Messages sent to the alias arrive in the primary mailbox and can’t be replied to from the alias address. It’s not suitable for shared team use. 

Shared mailboxes vs. ticketing systems 

When the management of shared mailboxes becomes difficult due to the number of people that need access, or the volume of queries to deal with, a ticketing system may be an appropriate solution. The ticketing system can integrate with the mailbox and captures emails, creating a unique ticket for each, so you can track, send, receive and monitor through the system, which is specifically designed for this purpose – making management much more efficient and organised. 

Tips for using shared mailboxes efficiently 

  1. Use categories, folders and archiving
 
    Organise incoming emails by tagging them or sorting into folders based on urgency, topic, customer or assigned team member. Make sure the entire team uses this consistently. Also set up an archiving strategy to remove old emails from the inbox. 
  1. Implement a clear ownership system 
    Assign ownership of specific folders and tasks to team members, ensuring this is followed. Use Outlook’s “assign to” feature to pass responsibility of certain emails to specific team members where required. 
 
  1. Enable “send as” or “send on behalf” 
    Control whether replies come from the shared mailbox or an individual user. For consistency, most teams prefer “Send as” the shared mailbox, however it is possible to configure even “send on behalf” emails to show in the shared mailbox sent items, for easier management. You can contact us here if you need support with this.
  1. Use rules, alerts and quick steps 
    Automate sorting, flagging, or forwarding of certain types of emails to increase efficiency and ensure nothing is missed. Create “quick steps” for actions that are performed regularly and to send standard responses to common queries.
 
  1. Set up auto-replies 
    Keep customers informed with automatic responses, especially during non-working hours or holidays.
 
  1. Monitor mailbox size 
    Regularly archive old messages or set up retention policies to prevent exceeding the storage limit.
 

Conclusion 

Shared mailboxes are a simple yet powerful feature within Microsoft 365 that enable teams to manage communication efficiently and professionally. While they’re not a one-size-fits-all solution, and may lack some advanced capabilities, they work exceptionally well for handling group emails, centralising communication, and enhancing collaboration. By understanding the differences between shared mailboxes, groups, and aliases, and by implementing a few best practices, your organisation can make the most out of this versatile tool. 

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