Updated: 2009-10-22

In this article:

This article describes the processes and data that are needed when you work with a Microsoft support engineer to identify and resolve calendar problems for unknown or undocumented causes.

Some common symptoms for calendar issues include the following:

For information about troubleshooting known issues with the Outlook calendar, see Microsoft Knowledge Base article 899704: Description of common scenarios in which Calendar information may be removed from the Calendar or may be inaccurate (http://go.microsoft.com/fwlink/?LinkId=125850), and Microsoft Knowledge Base article 890436: How to Troubleshoot missing and duplicate appointments in Outlook (http://go.microsoft.com/fwlink/?LinkId=125852). However, these two articles only provide information about known issues that can cause problems with the Outlook calendar data.

There are advanced methods that Microsoft support engineers use to analyze and determine the cause of several common issues related to the Microsoft Office Outlook calendar feature when you are using a Microsoft Exchange Server mailbox. To effectively troubleshoot a calendar issue, the support engineer will need a lot of information about your environment. The following sections provide an overview of the process and what information and logging configurations are needed when you work through the different stages of your support case.


For calendar issues that cannot be easily reproduced, you will need to gather and provide a lot of data for the Microsoft support engineer to effectively troubleshoot the issue. This is primarily due to the complexity of the Calendar feature set in Office Outlook and Exchange Server, and the varied scenarios and products that touch the data on a calendar. This includes, but is not limited, to the following items:

  • Delegate/manage scenarios

  • Cached Exchange Mode versus Online mode

  • Third-party interaction (for example, BlackBerry, iPhone, or GoodLink)

  • Outlook Web Access (OWA) interaction

  • Entourage interaction

Before reviewing the different tools and data that are required to troubleshoot calendar issues in Outlook, it is important to recognize and understand some key points about these issues.

  • A missing or corrupted meeting often cannot be recovered. You might try to delete and re-create the meeting.

  • Without all the data requested, the support engineer will not be able to definitively determine why there is a problem with the meeting item.

  • The best possible information that you can offer to Microsoft support engineers is specific, reproducible steps that lead to a problem. For example:

    1. User1 sends a meeting request to User2.

    2. User2 accepts the request.

    3. User1 synchronizes their calendar with a hand held device.

    4. User1 makes an update to the meeting and sends the update to User2.

    5. User2 gets an error message when trying to accept the meeting update.

    By using this kind of information, we can eliminate many of the tools and steps listed in this article to diagnose the problem. However, even with consistently reproducible steps, your support engineer will require a significant amount of data (such as log files, configuration settings, and third-party software information) to analyze the problem.

  • Data is also required from your servers (Exchange, BlackBerry, or GoodLink) and clients. If your organization is segmented into client and server groups, it is most effective to bring in a representative from each group to work on your support case. You might need logs, configuration settings, history of hotfix installations, and other related details from your servers and clients.

  • The users who are affected most often are high-profile users who have many meetings. Some of the data for these cases can only be obtained from the affected user's workstation. It is recommended that you obtain this required information as soon as possible after you open the support case.

  • When you open a support case, you will be provided a list of tools that must be run and data that must be gathered. You will need to provide a date on which you will have all of the preliminary requested items required for troubleshooting the issue.

  • Once you provide all the preliminary data, you and the support engineer will agree to a date on which the case would be temporarily closed if the problem does not recur. If the case is temporarily closed and the issue recurs, your support engineer will ask for all of the requested items to reopen the case. You may also have to gather new information and logging data if the items you provide are out of date or no longer relevant.

Preliminary data to gather and logging to enable

After you open a Microsoft support case, the following list of actions must be completed before the next occurrence of the calendar issue.

  1. Select one user for which the calendar issue occurs most often to be the focus for the case.

  2. For scenarios where the affected user has a BlackBerry, iPhone, or GoodLink device:

    a. It is recommended that you open a support case with Research in Motion (RIM), Apple, or Motorola Good Technology, respectively. Early involvement of third-party vendors has been shown to be helpful in resolving these calendar issues more quickly than if they are either not involved or involved late in the case.

    b. When you open a case, ask the support engineer at either RIM, Apple, or Motorola to:

    • Make sure the server or device is at the most recent service pack or hotfix level.

    • Check if you are encountering a known issue.

    • Make sure the server (BlackBerry or GoodLink only) has the latest supported version of Cdo.dll.

    Enable logging so that the support engineer can review these logs after the problem occurs.

    c. Gather all the BlackBerry, iPhone, GoodLink, or handheld sync and Cdo.dll information, and provide this information to the support engineer.

    • BES/iPhone/GoodLink version

    • Service pack level

    • Cdo.dll version on BES or GoodLink servers

    • Client sync software name and version (if applicable)

  3. If you are using a different third-party device or third-party software to manage Outlook and Exchange calendar data, you should provide the support engineer with the product details. It is also recommended that you open a support case with the third-party vendor to enable any available logging in the product.

  4. Gather a Process Explorer dump from the user's computer and from all delegate computers. The Process Explorer generates a list of DLLs that are running under the Outlook.exe process. If there are any third-party DLLs that are running under the Outlook.exe process and logs indicate that they might be causing the problem, you might be requested to disable some or all of them. For detailed information about Process Explorer, see Processes and Threads: The Process Explorer (http://go.microsoft.com/fwlink/?LinkId=125853). For detailed information about how to use Process Explorer, see Microsoft Knowledge Base article 970920: Using Process Explorer to List dlls Running Under the Outlook.exe Process (http://go.microsoft.com/fwlink/?LinkId=153876).

  5. Provide a list of installed add-ins including the information from the following registry hives:




  6. Provide a minimum of two screen shots of the delegate settings for this user. Include one screen shot of each of the following:

    a. The Delegates tab in Outlook listing all the delegates for the user.

    b. The Permissions dialog box, found under the Delegates tab, for each delegate.

    Because there are several configurations possible for an Outlook delegate, it is important to understand how the delegate is configured to receive and process meetings for the manager. When logging data is analyzed, the delegate configuration is required to put the data into the appropriate context.

  7. If either manager or delegate is using Office Outlook 2007, try to make sure both are using Office Outlook 2007 with Service Pack 2 or later. For information about this recommendation, see Microsoft Knowledge Base article 924470: When you use delegates in Outlook 2007, it is recommended that the manager and all the delegates use Outlook 2007 Service Pack 2 (http://go.microsoft.com/fwlink/?LinkId=167917).

  8. For Office Outlook 2003 or Office Outlook 2007, enable Outlook logging on the calendar owner's computer and all delegate computers, and then restart Outlook. The client-side calendar logging data can indicate if meeting changes are being done by a delegate or third-party software. It also helps put the other logging data into the appropriate context. For information about enabling calendar logging, see Microsoft Knowledge base article 841615: Description of the Calendar logging feature in Outlook (http://go.microsoft.com/fwlink/?LinkId=125854).

    If you are using either Outlook 2000 or Outlook 2002, it is recommended that you upgrade the affected user's computer to at least Outlook 2003 to enable client-side logging for Outlook.

  9. For scenarios involving Entourage, gather the following information:

    a. Version and build number of Entourage (on the Entourage menu, click About Entourage).

    b. Screen shots of all five tabs by using Tools - Accounts - Mail - Exchange Account Settings in Entourage.

    With this information, we will determine whether you are connecting to an Exchange front-end or back-end server and whether it is possible to take a client-side trace (if needed) to help troubleshoot the issue.

  10. Instruct the affected user and delegates to not delete any meetings, invitations, or calendar-related items from their Inbox, Deleted Items, Sent Items, Calendar, Sync Issues and Conflicts folders.

    The analysis of calendar logging data usually indicates who acted on an item and when. Therefore, it is important to corroborate the logging information with the actual items related to the meeting.

  11. Enable the DumpsterAlwaysOn registry value for Outlook 2003 or lower. By having the DumpsterAlwaysOn registry value set to 1, Outlook maintains hard-deleted items in each folder up through the retention period specified for the Exchange Server computer. For information about how to enable this registry value, see Microsoft Knowledge Base article 246153: How to recover items that have been hard deleted in Outlook (http://go.microsoft.com/fwlink/?LinkId=125856).

  12. Verify that you have Deleted Item Retention configured for the Exchange Server computer for an appropriate length of time to recover any deleted items.

  13. Enable store tracing for the user's mailbox on the Exchange store. Exchange store tracing is one of the most important items to enable, collect, and analyze with calendar issues. However, as with other logging data, the findings in the Exchange store log must be corroborated with the other data gathered.

    The logging steps vary according to the version of Exchange Server that is used. For Exchange Server 2007, see Microsoft Knowledge Base article 971878: Steps to enable Exchange 2007 store tracing for calendar issues (http://go.microsoft.com/fwlink/?LinkId=153878). For Exchange Server 2000 or Exchange Server 2003, see Microsoft Knowledge Base article 971435: Steps to enable Exchange 2000 and Exchange 2003 Calendar Store tracing (http://go.microsoft.com/fwlink/?LinkId=153879). Your support engineer can help you with this process.

  14. Verify store logging is working. Enable store logging and check to see that the log is actually getting data added to it.

Data to provide for analysis after the problem recurs

When the designated user reports another occurrence of the calendar issue, gather all the following items or details and contact the Microsoft support case owner.

  1. Details for the meeting where the problem occurred:

    Organizer name


    Start/end Times

    Recurrence Information — For a recurring meeting, is the problem with the complete series or just one occurrence in the series?

    Was it a meeting update or a new meeting?

    When did they last notice the item correctly appearing in the calendar?

    When did they notice the problem occurring?

  2. Name and alias for the affected user and their delegates.

  3. Any actions taken by anyone involved (such as update, accept, or BlackBerry, iPhone, or GoodLink access).

  4. For missing meeting issues:

    a. Look to see whether the item appears when you change the view on the user's Calendar folder to a tabular view.

    For example, in Office Outlook 2007 you can switch to a tabular view by using View - Current View - By Category.

    b. Check the Deleted Items folder for all relevant users to see whether there is a related item in the folder.

    If a related item is found:

    i. Copy the item to a new .pst file.

    ii. Leave the item in the Deleted Items folder.

    c. With the Calendar folder selected, go to Recover Deleted Items on the Tools menu to see whether the meeting is in the dumpster.

    If found in the dumpster:

    i. Recover the item.

    ii. Copy the item to a new .pst file.

    iii. Leave the recovered item in the Calendar folder.

  5. Conflict resolution messages from the client (if any) from owner and delegate computers.

    a. Switch to the Folder List module in the navigation pane.

    b. Select the Sync Issues folder.

    c. Look for any messages that have "Modification Resolution" as the subject.

    d. Copy any messages that have "Modification Resolution" as the subject to a .pst file.

  6. Conflict messages from the client from owner and delegate computers (if any).

    a. Switch to the Folder List module in the navigation pane.

    b. Select the Conflicts folder.

    c. Copy any meeting related items in the Conflicts folder to a .pst file.

  7. Client log files from owner and delegate computers.

    Outlook 2003 and Outlook 2007 with SP1 calendar log files are named Logcalb# (where # is an index number starting at 2) and are found in the %temp% folder on the user's computer.

    There will be many Logcalb files (because a new one is generated every time that you start Outlook); therefore, you only need the ones from around the time the problem occurred. For example, if the problem occurs on Wednesday, gather all Logcalb files for Tuesday and Wednesday. If you are using Outlook 2007 SP2 (or later), Outlook also generates an improved calendar log file in the %temp%\OLKCalLogs folder. The new files are named OLKCalLog_<date_time>.etl where <date_time> is a time stamp for when the file was last saved. Therefore, if you are using Outlook 2007 SP2 (or later), collect the following files:

    • %Temp%\Logcalb#

    • %Temp%\OlkCalLogs\OLKCalLog_<date_time>.etl

  8. Exchange Server store log.

    For Exchange Server 2000 or Exchange Server 2003, stop logging on the Exchange Server computer by setting the Enable Tracing value to 0. Then, gather the Store.log file from the \Exchsrvr\Bin folder.

    For Microsoft Exchange Server 2007, the name and location of the trace file is configured when you run EXTRA.exe. By default, it is Documents and Settings\administrator\ExchangeDebugTraces.etl.

  9. Additional data.

    The support case engineer will help you gather additional data (such as the output of the item properties by using the MAPI Editor Tool) and to collect all of the log files and screen shots listed in the previous section of this article.