For diagnostic purposes, Microsoft Outlook for Windows contains an option that turns on logging for certain Outlook features. These logs can be helpful for support staff who are troubleshooting problems.
In this article
- Turn logging on or off
- What information does logging record?
- Log file locations
- Administrator information
Turn logging on or off
Important
Turn off logging after you complete your troubleshooting. If you don’t turn off logging, the log files continue to increase in size.
- In Outlook, go to the File tab > Options > Advanced.
- Under Other, select or clear the Enable troubleshooting logging (requires restarting Outlook) check box.
- Exit and restart Outlook.
Note
- After you restart Outlook, if mail logging is turned on, (Logging Enabled) appears in the Outlook title bar.
- You may have to exit Outlook for data to be written to the log files.
What information does logging record?
The logging option logs information about the following features:
Calendar transactions that are generated by Outlook features, by user actions, by the object model, or by the MAPI Calendar Table, including:
- Inbox autoprocessing
- Free/busy publishing
- Reminders
- Calendar item actions (creation, modification, or deletion)
- Resource booking
The main purpose of the calendar logging feature is to quickly identify situations where, for example, meetings are inexplicably deleted from a calendar folder.
Free/busy time changes
Offline Address Book
Transactions for the Messaging Application Programming Interface (MAPI), which is used with Microsoft Exchange, POP3, Internet Message Access Protocol (IMAP), Simple Mail Transfer Protocol (SMTP), and Lightweight Directory Access Protocol (LDAP).
A unique log file is generated for each Send/Receive action that you perform on these accounts.Communications with Exchange, POP3, SMTP, and IMAP servers.
Viewing the log files
Most log files are in plain text. To protect your data, the calendar log file is a binary file that can’t be read without a conversion process. Contact Microsoft Support for more information about calendar log files.
Log file locations
The log files are stored in subfolders of the Temp folder. By default, your Temp folder is located in your \AppData\Local folder:
- c:\Users\username\AppData\Local\Temp
By default, the Local Settings and AppData folders are hidden.
To display hidden folders in Windows, do the following:
In Windows, open Control Panel.
Open Folder Options.
- To locate Folder Options, in the search box at the top of window, type Folder Options.
On the View tab, under Advanced settings, under Files and Folders, under Hidden files and folders, select Show hidden files, folders, and drives.
The following table shows the location and content of the various plain text log files.
| Type of log file | Subfolder | File name |
|---|---|---|
| Outlook Autodiscover | Temp | olkdisc.log |
| Exchange ActiveSync | Temp/EASLogFiles | datafilename.bin datafilename.xml |
| Availability service | Temp/OlkAS | date-time-fb.log |
| Availability service, OOF, and meeting suggestion | Temp/OlkAS | date-time-AS.log |
| Protection rules | Temp/OlkAS | date-time-PB4S.log |
| Unified messaging | Temp/OlkAS | date-time-UM.log |
| Unified messaging configuration | Temp/OlkAS | date-time-UMCFG.log |
| Out-of-office | Temp/OlkAS | date-time-oof.log |
| Meeting suggestion | Temp/OlkAS | date-time-ms.log |
| Outlook calendar | Temp/OlCalLogs | OLKCalLog_date-time.etl |
| Transport | Temp/Outlook Logging | opmlog.log |
| SMTP | Temp/Outlook Logging | emailaddress-Outgoing-date-time.log |
| POP3 | Temp/Outlook Logging | emailaddress-Incoming-date-time.log |
| IMAP | Temp/Outlook Logging | IMAP-emailaddress-Incoming-date-time.log |
| HTTP DAV | Temp/Outlook Logging | HTTP-emailaddress-date-time.log |
| Outlook Hotmail Connector | Temp/Outlook Logging | OLC-emailaddress-date-time.log OLC-date-time.log emailaddress.txt |
| Out-of-office | Temp/Outlook Logging | date-time-oof.log |
| Outlook profile | Temp/Outlook Logging | PROF_OUTLOOK_threadID_action_year.month.day_hour.minute.second.txt |
| Outlook sharing engine | Temp/Outlook Logging | Sharing Enginedate .log |
| Outlook-Windows Desktop Search indexing | Temp/Outlook Logging | datafilename.log |
| Outlook advanced ETW | Temp/Outlook Logging | Outlook-date-time.etl |
| Mailtips | Temp/Outlook Logging | date-time-mailtips.log |
| Free busy | Temp/Outlook Logging | date-time-fb.log |
| Outlook Sharing Engine | Temp/Outlook Logging | Sharing Enginedatetime-mailtips.log |
| Outlook first run process | Temp/Outlook Logging | firstrun.log |
Administrator information
As an administrator, you can use the registry to turn logging on or off, and you can also deploy logging settings to users.
For information about how to turn logging on and off by using the registry, see Microsoft KB 831053.
Default Outlook logging settings can be configured in the Office Customization Tool (OCT) on the Modify User Settings page, or you can enforce the settings by using the Outlook Group Policy template (Outlk15.adm) in the Local Group Policy Editor.
Important
Because of performance and security reasons, we don’t recommend that you deploy the logging feature. Turn on the logging feature only when needed.
To enforce logging settings for Outlook users, do the following:
- In Group Policy, in the Outlook 2013 policy template Outlk15.adm, under User configuration\Administrative templates\Microsoft Outlook 15\Tools | Options\Other\Advanced, double-click Enable mail logging (troubleshooting). Select Enabled to enable configuring the settings.
- Select or clear the Enable troubleshooting logging (requires restarting Outlook) check box.