The remote procedure call (RPC) Cancel Request dialog box is a feature that was added in Microsoft Outlook 2002. With this feature, users can see the server that Outlook is accessing. Additionally, by using the Cancel Request dialog box, users can cancel the data retrieval.
When Outlook 2002 and later versions request data from an Exchange Server computer, Outlook calls a function that wraps the RPC to the server. This new wrapper is the Cancelable RPC wrapper. By default, the Cancelable RPC wrapper starts a timer and issues the RPC. When the RPC is complete, the wrapper closes the timer, cleans up, and quits. However, if the RPC for data takes more than 5 seconds to return the data, the wrapper produces the Cancel Request dialog box. The Cancel Request dialog box remains on the screen until the RPC is answered or until the user clicks Cancel. If the action that the user performs in Outlook causes multiple RPCs to be made, the user may receive a Cancel Request dialog box for each RPC.
Although the Cancel Request dialog box was intended to improve the user experience by providing server information when Outlook stopped responding, many users interpret this message as an error message and contact their help desk for more information, instead of understanding that the Cancel Request dialog box occurs as an ordinary part of Outlook and Exchange interoperation. On the fastest network with the best hardware and the best architecture, sometimes an RPC takes more than 5 seconds to obtain a response. If the Cancel Request dialog box appears only occasionally, 'extensive troubleshooting is not required and is not productive. However, if users receive the Cancel Request dialog box frequently and for extended periods, there may be a performance issue with one of the servers or a problem with the network. This article discusses troubleshooting steps that you can use to determine the root cause of frequent Cancel Request dialog boxes.
For more information about how to disable the Cancel Request dialog box feature or how to increase the time-out value if you experience frequent network congestion or other related issues, click the following article number to view the article in the Microsoft Knowledge Base:
- Gather the following information about what the user is doing when the user receives many Cancel Request dialog boxes:
- Is the user browsing a Public Folder that is located in another Administrative Group without having a replication of this folder in their own site?
- Is the user opening a meeting with many attendees?
- Is the user creating or updating a meeting to check the free/busy information for the attendees?
- Consider the Active Directory and Exchange architecture of your environment. Answer the following questions:
- Are the global catalog servers located locally or remotely?
- Does connectivity to the remote site pass through routers and through firewalls?
- Are there dedicated Public Folder servers?
- Where are the system folders homed?
A hotfix is available to modify the way that Exchange Server 2003 handles a disabled Active Directory user account that is associated with an Exchange Server 2003 mailbox. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
If you see many 1016 events in the application event log on the Exchange Server computer, your issue may be caused by users who are creating and updating calendar items. In this scenario, it may be a good idea to disable the Planner Options feature for testing purposes. Planner Options is a feature that was originally introduced in Outlook 2002. Planner Options gathers much more data than earlier versions of Outlook if the Scheduling tab is clicked when a user creates, updates, or reads about a meeting. If disabling this feature resolves the excessive RPC dialog boxes, you must determine if disabling this feature works for your business. If the Planner Options feature is disabled, the user can see the attendee's free/busy information, but additional details are not viewable.
How to turn off the Planner Options featureFollow these steps to turn off the Planner Options feature:
- On the Tools menu, click Options.
- On the Preferences tab, click Calendar Options.
- In the Calendar Options dialog box, click Planner Options.
- In the Meeting Planner section, click to clear the Show popup calendar details check box.
- Click OK three times.
- On the Tools menu, click Options, and then click the Other tab.
- Under Person Names, click to clear the Enable Person Names Smart Tag check box, and then click to clear the Display Messenger Status in the From Field check box.
- Click OK.
Method 2Administrators can also turn this feature off by changing the Enabled registry value to 0 in the following registry subkey:
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
- Click Start, click Run, type regedit, and then click OK.
- Locate and click the following registry subkey:HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\IM
- In the right-pane, click Enabled.
- On the Edit menu, click Modify.
- In the Value data box, type 0, and then click OK.
- Quit Registry Editor.
For additional information about how to determine if this issue occurs with a new Outlook profile, click the following article numbers to view the articles in the Microsoft Knowledge Base:
- On the Tools menu in Outlook, click Options.
- Click the Other tab, and then click the Advanced Options button.
- Click the Add-In Manager button.
- Click to clear the check box for any third-party add-ins that may be selected.
- Click OK three times.
- Restart Outlook.
If the RPC dialog references an Exchange Server (NetBIOS name), configure Performance Monitor to monitor the following counters in real time:
Physical Disk (All Instances)
- Avg Disk Sec/Read
- Avg Disk Sec/Write
- Current Disk Queue Length
- RPC Averaged Latency
- RPC Requests
- RPC Operations/Sec
- %Processor Time
Database (Information Store Instance)
- Log Record Stalls / sec
Note It is a good idea to run Performance Monitor from a remote workstation that has lots of free disk space.
Typically, it is a good idea for the RPC Requests counter to be lower than 10. If it is higher than 25, this is an indicator of a resource bottleneck. Only 100 requests can be handled at the same time. If the RPC Requests reach 100, the client will experience refused connections.
The RPC Averaged Latency counter displays the average time that it takes the server to respond to client requests. The value of the counter is typically less than 50 milliseconds in typical operations. If the value is consistently more than 50 milliseconds with Outlook 2002 or Outlook 2003 when most of the users are in Online Mode, this means that the Information Store is taking a long time to process user requests. If most Outlook 2003 users are in Cached Mode, this threshold increases to 100 milliseconds. Typically, if the Information Store is taking a long time, there is a disk bottleneck.
The recommended values for the Avg Disk Sec/Read counter and for the Avg Disk Sec/Write disk counter are as follows:
- Good < 20 msec
- Fair < 30 msec
- Poor < 40 msec
- Cache/Exec < 1 msec
- Cache/Good < 2 msec
- Cache/Fair < 4 msec
Note It is not unusual to see brief spikes that are greater than .050, but if you are seeing counters greater than .050 for 30 to 60 seconds at a time, there probably is a problem.
To determine if there is a problem with the current disk queue length, see how frequently the value drops to zero. If the queue length drops to zero periodically, such as four times per minute, the queue is being cleared, and you probably do not have a disk bottleneck.
it is a good idea for the Log Record Stalls/sec counter to remain at 0. If you are seeing a high number of log stalls on an Exchange 2000 Server computer, change the value of the msExchESEParamLogBuffers property. For more information about changing the value of the msExchESEParamLogBuffers property, click the following article number to view the article in the Microsoft Knowledge Base:
Discussing how to configure and to use a protocol sniffer is outside the scope of this article. However, if you are already familiar with using such a utility, it is a good idea to reproduce the issue while you monitor traffic on both the client and the server at the same time. When you analyze the data, look for retransmits. A retransmit occurs when the client or the server has to send the same packet of information again, typically because the packets are being dropped between the client and the server. Therefore, when you analyze network captures, determine if the client request is actually getting to the server or if the server is responding but the response is lost before the client receives it.
How to change RPC dialog box pop-up behaviorFor more information about how to disable the Cancel Request dialog box feature or how to increase the time-out value if you experience frequent network congestion or other related issues, click the following article numbers to view the articles in the Microsoft Knowledge Base:
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.
Article ID: 839862 - Last Review: Aug 19, 2009 - Revision: 1