concurrent connections on mailboxes and shared mailboxes in exchange online

pazzoide76 301 Reputation points
2022-10-18T14:14:08.973+00:00

Hello,
I have a question about concurrent connections on mailboxes and shared mailboxes in exchange online.
How many users can access the same mailboxes at the same time using Outlook?
How many users can access the same shared mailboxes at the same time using Outlook?

Thank you

Greetings

Outlook Management
Outlook Management
Outlook: A family of Microsoft email and calendar products.Management: The act or process of organizing, handling, directing or controlling something.
4,981 questions
Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,426 questions
{count} votes

Accepted answer
  1. Vasil Michev 98,111 Reputation points MVP
    2022-10-18T14:26:01.927+00:00

    Microsoft does not publish throttling settings information for Exchange Online, so we cannot give you an exact number. If you are facing any performance issues with accessing shared mailboxes, refer to the suggestions in this article: https://learn.microsoft.com/en-us/outlook/troubleshoot/performance/slow-performance-if-having-many-shared-folder-or-mailboxes-open
    As general rule, try to keep the connections to a minimum, do not use Automapping unless you need continuous access to the shared mailbox, reduce the size of the mailbox, the number of folders and the size and the local cache where possible. Consider accessing the shared mailbox via OWA where it makes sense.


3 additional answers

Sort by: Most helpful
  1. Christian Lipp 1 Reputation point
    2022-10-18T14:19:52.797+00:00

    Here are the limitations about Exchange Online Mailboxes:

    Best

    0 comments No comments

  2. pazzoide76 301 Reputation points
    2022-10-18T14:44:14.693+00:00

    ChristianLipp-9479 the link you posted doesn't work.
    Michev the same goes for normal mailboxes?
    I have a customer who on exchange onprem about 50 users access the same mailbox through outlook.
    So for this customer exchange online it is not the correct solution.
    Right?


  3. Mike Russo 16 Reputation points
    2024-02-15T16:03:25.8466667+00:00

    Microsoft finally updated a new doc to mention a 25 user limit - but they really mean "outlook client". That tracks with what I've seen. Avoid if possible having users open the shared mailbox from multiple computers. And add access without automapping and then add into Outlook directly so that it only connects from the Outlook you want it to connect from. New doc link: https://learn.microsoft.com/en-us/microsoft-365/admin/email/about-shared-mailboxes?view=o365-worldwide

    0 comments No comments