About Microsoft Exchange Server account device limits

Microsoft Exchange Server 2010 sets a limit of ten mobile devices that can connect to each Exchange account. Microsoft calls these connections "partnerships."

This article is intended for an Exchange Server administrator. If you experience any of these issues, contact your institution's Exchange Server administrator.

If you set up an account on an iPhone, iPad, or iPod touch that exceeds the limit, you might see these issues:

  • The profile doesn’t install.
  • You can't sync Mail, Calendar, or Notes with the Exchange account.
  • When you check email on the desktop client or Outlook Web Access, you see this message: "Error with your new mobile phone partnership. You have 11 phone partnerships out of the maximum allowed 10 partnerships."

If you exceed the 100-device limit set in later versions of Exchange and Office 365, you might see similar issues.

Remove mobile device partnerships

  1. Sign in to the Outlook Web App.
  2. In the upper-right corner of the toolbar, click the gear icon (), then select Options.
  3. In the Options list, select Phone.
  4. In the list of mobile devices, delete any partnerships that you don’t use. Make sure that ten or fewer devices are associated with the account.

Your can increase the number of mobile device partnerships that ActiveSync allows for on-premise servers. To increase the limit, change the EASMaxDevices parameter of the client throttling policy.

Learn how to set client throttling policies for Exchange 2010Exchange 2013, and Exchange 2016. Learn more about client throttling policies for Exchange 2010Exchange 2013, and Exchange 2016.

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