Use Logging to Troubleshoot Email Problems in Outlook

Set up email logging when Outlook isn't working

LOG file

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When an unexplained email error doesn't go away and rebooting your computer doesn't fix the problem, enable logging in Outlook and inspect the LOG file. The LOG file contains a detailed list of what Outlook did while sending and receiving messages. With this special LOG file, you can either pinpoint the problem yourself or show it to your ISP's support team for analysis.

Instructions in this article apply to Outlook 2019, Outlook 2016, Outlook 2013, Outlook 2010, and Outlook for Microsoft 365.

Enable the Transaction Log

To enable logging in Outlook:

  1. Go to File > Options.

    Outlook Options
  2. In the Outlook Options dialog box, select the Advanced tab.

    Advanced tab Outlook Options
  3. In the Other section, select the Enable troubleshooting logging check box.

    Enable troubleshooting logging
  4. Select OK.

  5. Close and restart Outlook.

  6. When Outlook opens, a notification appears that explains that logging is enabled and may cause performance problems.

Troubleshoot Outlook Issues

After logging is enabled, reproduce the problem so that you can inspect the log. After you've encountered the same error, disable logging (from the Outlook Options dialog box), restart Outlook, then find the Outlook LOG file.

To locate the LOG file:

  1. Press the Win+R keyboard shortcut.

  2. In the Run dialog box, enter %temp% and press Enter.

    Run dialog
  3. In the Temp folder, locate the LOG file. The file name depends on the problem and the type of email account.

    • POP and SMTP: Open the OPMLog.log file if your account connects to a POP server or if you have trouble sending email.
    • IMAP: Open the Outlook Logging folder and then the folder named after your IMAP account. From there, open imap0.log, imap1.log, or another file in the sequence.
    • Hotmail: If a Hotmail email account signed on through Outlook, open the Outlook Logging folder, choose Hotmail, and then find http0.log, http1.log, or another file in the sequence.
  4. Select the file to open it.

The LOG file can be read in any text editor such as Notepad in Windows and TextEdit in macOS. Or, there are several free text editors if you would rather use something a bit more advanced.


The LOG file offers technical guidance about problems, but the output may not be easy to parse. Because a wide variety of problems may adversely affect Outlook, paste key terms from the error message into your favorite search engine to fine-tune your troubleshooting steps.

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