Throttling policy throttles all EWS applications in Exchange Server 2010

Symptoms

Consider the following scenario:

• Client throttling policies for Exchange Web Service (EWS) are enabled in a Microsoft Exchange Server 2010 environment.
  
  Note By default, all client throttling policies are enabled in Microsoft Exchange Server 2010 Service Pack 1 (SP1) or in Microsoft Exchange Server 2010 Service Pack 2 (SP2).

• An EWS application that runs on behalf of a user quickly consumes resources on the Exchange server. The operations that the EWS application performs exceed the limit that is set in the client throttling policies.

In this scenario, all EWS applications that run on behalf of the user are throttled unexpectedly.

Note The expected behavior is that only the EWS application whose operations exceed the limit that is set in the client throttling policies is restricted.

Cause

This issue occurs because all the EWS applications that run on behalf of the user consume the same client throttling policy budget.

Resolution

To resolve the problem, install Update Rollup 4 for Exchange Server 2010 Service Pack 2. For more information about this update rollup, click the following article number to view the article in the Microsoft Knowledge Base:

2706690 Description of Update Rollup 4 for Exchange Server 2010 Service Pack 2

More Information

For more information about Client Throttling Policies, go to the following Microsoft website:

General information about client throttling policiesFor more information about throttling budget calculation, go to the following Microsoft website:

Exchange API-spotting

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.