Microsoft Outlook: Is there a limit to the number of users that can access a Shared Calendar and its related contacts?

Steph in Vero Beach 6 Reputation points

Our company uses a specific calendar and the associated contacts as a central location for scheduling and as an address book. All users can view and edit both the calendar and the contacts. Users are also adding this account to mobile devices for quick access to the "Address Book" and to confirm meetings or availability of meeting space. We are beginning to run into issues where users are being signed out of that account randomly. It would seem that there is a limitation of the number of users? Can you please confirm if there is indeed a limitation and if so, indicate if there is a way to increase the number of users or provide an alternative solution?

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.
4,939 questions
{count} vote

1 answer

Sort by: Most helpful
  1. ChristyZhang-MSFT 21,181 Reputation points Microsoft Vendor

    Hi @Steph in Vero Beach ,

    Welcome to our forum!

    Is your shared mailbox based on Exchange online or premises?

    As I know, if it is Exchange online, when there are too many designated users concurrently accessing a shared mailbox (no more than 25 is recommended), they may intermittently fail to connect to this mailbox or have inconsistencies like messages being duplicated in the outbox. References: About shared mailboxes.

    If it is Exchange premises, please refer to this article: Managed Store Limits in Exchange Server.

    Hope to help you!

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.