Outlook.exe.log file in the %Temp% folder consumes too much disk space


In your computer's %Temp% folder, you notice a very large file (for example, more than 1 GB) that's named Outlook.exe.log.

Note The %Temp% folder is typically found at C:\Users\<user name>\AppData\Local\Temp.


This problem may occur if you turned on TCOTrace logging by enabling the following registry settings:

Key: HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Common\Debug
Value: 1

Note The x.0 placeholder represents your version of Office (16.0 = Office 2016, 15.0 = Outlook 2013, 14.0 = Outlook 2010, and 12.0 = Outlook 2007).

TCOTTrace logging should remain enabled only as long as you are working with a support engineer on a specific issue.


To resolve this issue, follow these steps:

  1. Exit Outlook.
  2. Open a Run dialog box. To do this, use one of the following methods, as appropriate for your situation:
    • Windows 10, Windows 8.1 and Windows 8: Press Windows Key + R.
    • Windows 7 or Windows Vista: Click Start, and then click Run.
  3. Type regedit.exe, and then click OK.
  4. Locate and then click the following subkey:

    Note The x.0 placeholder represents your version of Office (16.0 = Office 2016, 15.0 = Outlook 2013, 14.0 = Outlook 2010, 12.0 = Outlook 2007).
  5. Right-click TCOTrace, and then click Delete.
  6. When you are prompted to confirm the deletion, click Yes.
  7. On the File menu, click Exit to exit Registry Editor.
  8. Delete the Outlook.exe.log file from the %Temp% folder if you are not working with a Microsoft support engineer on an issue.

Article ID: 3038305 - Last Review: Jan 13, 2016 - Revision: 1

Outlook 2016, Microsoft Outlook 2013, Microsoft Outlook 2010, Microsoft Office Outlook 2007