SharePoint 2010: "Check names" results in "Item cannot be more than 256 characters"

Article ID: 2654222 - View products that this article applies to.
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Consider the following scenario:

You copied a series of users as a string from Outlook and pasted it into a User Control inside a SharePoint 2010 site.
You click on the "Check Names" icon and get the following error message: 

"Item cannot be more than 256 characters."

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Error Message - Item cannot be more than 256 characters


This is a by-design behavior which has been introduced in SharePoint 2010 as a security measure.


You still can insert up to 200 users inside a SharePoint 2010 user control box. You just need to use the "Check Names" control in smaller batches.
For example, you insert a number of users that add up to less than 256 characters and click the "Check Names" control. You then add another batch of users and click "Check Names", and so on until you have added and resolved all of the desired users.

More Information

The limitation of 200 users is defined by property DefaultMaximumEntities of Class PeopleEditor.

For more details, please check this MSDN article:

Note This is a "FAST PUBLISH" article created directly from within the Microsoft support organization. The information contained herein is provided as-is in response to emerging issues. As a result of the speed in making it available, the materials may include typographical errors and may be revised at any time without notice. See Terms of Use for other considerations.


Article ID: 2654222 - Last Review: January 10, 2012 - Revision: 5.0
  • Microsoft SharePoint Server 2010
  • Microsoft SharePoint Foundation 2010

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