Description of the Calendar logging feature in Outlook

Applies to: Microsoft Office Outlook 2007

For steps to enable logging in Microsoft Office Outlook 2010 and 2013, see 2260527 .


Microsoft Office Outlook has a feature to log calendar transactions. Because of the Calendar logging feature, calendar transactions that are generated by client features, by user actions, by the object model, or by the MAPI Calendar Table are written to a log file. The log file contains information for the following items:
  • Sniffer (Inbox auto-processing)
  • Free/busy publishing
  • Reminders
  • Calendar item actions (creation, modification, or to deletion)
  • Resource booking
The main goal of the Calendar logging feature is to quickly identify situations where, for example, meetings are inexplicably deleted from a Calendar folder.

More Information

This article describes the following information about the Calendar logging feature:
  • Configuration
  • Log file creation
After you have configured Outlook for calendar logging, the log file is created after you restart Outlook. A new log file is created every time that you start Outlook until you disable the calendar logging option.


To turn on the Calendar logging feature, follow these steps:
  1. On the Tools menu, click Options.
  2. On the Other tab, click Advanced Options.
  3. Click to select the Enable Logging (troubleshooting) check box, and then click OK two times.
  4. Restart Outlook.
After you restart Outlook, the words “Logging Enabled” in the title bar indicate that you have a visual indication that the Calendar logging feature is turned on. When logging is completed, you can disable logging by using the same steps. Also, you can reenable Cached Exchange Mode by using the same steps.

Additionally, you can use the Custom Installation Wizard (CIW), the Custom Maintenance Wizard (CMW), the Office Customization Tool (OCT), or a system policy to deploy the setting for the Calendar logging feature. The following registry data is applied when you use these methods to deploy the setting for the Calendar logging feature:

For a system policy:


For CIW or CMW:


Value: EnableLogging
Data: 0=disabled (default, if registry data does not exist); 1=enabled

For OCT:


Value: EnableLogging
Data: 0=disabled (default, if registry data does not exist); 1=enabled

Because of performance and security reasons, we do not recommended that you deploy the Calendar logging feature. You should only turn on the Calendar logging feature on an as-needed basis.

Log file creation (pre-Outlook 2007 SP2)

When you start Outlook with the Calendar logging feature turned on, a log file is automatically created in the %temp% folder. By default, this is the \documents and settings\<username>\local settings\temp folder. The naming convention for the log file will use the following rules:
  • The file name will be Logcalb#, where # is an integer that starts with the number one.
  • Every time that you start Outlook, a new log file is created and the index number on the end of the file name is incremented by 1.
  • If you are low on disk space, a log file is not created.
To help protect customer data, the log file is a binary file that cannot be read without a conversion process. You can upload the log file to a secure FTP location and contact Microsoft Product Support Services. A Support Engineer from Microsoft can download and convert the log file. The Support Engineer can, at that time, upload the converted log file to the FTP site for your analysis. The Support Engineer can also perform the log file analysis for you.

Log file creation (Outlook 2007 SP2 and later versions)

Additional calendar logging was added to Outlook 2007 SP2. Now, if you enable Outlook logging, Outlook 2007 SP2 creates two different Calendar log files:
Note Every time that Outlook starts, a new OlkCalLog file and Logcalb file are created.