How to read Microsoft 365 Outlook logging etl file ?

Question

Hello,

can somebody give me a hint how to read etl file generated by outlook when I tick "Enable troubleshooting logging" in Outlook advanced option.

It saves files to c:\users\username\appdata\temp\outlook logging\

If I open them in event viewer, it shows me all events, but everything inside even is blank.

Thank you.

Answer 1

They must be converted and analyzed with internal tools by Microsoft Support ?

Shame on Microsoft. How can admins troubleshoot such issues if logs are not exist ?

Gold old ages where logs were for everything. Now only vendor is able to analyzing the logs with internal tools. That's weird.

Answer 2

The .etl files created when “Enable troubleshooting logging” is turned on in Outlook are advanced Event Tracing for Windows (ETW) trace logs. These logs are intentionally stored in a binary format and are not meant to be read directly in Event Viewer or by end users.

They must be converted and analyzed with internal tools by Microsoft Support. The documented process is:

1. Enable logging and reproduce the Outlook issue.
2. Collect the generated .etl files from the Temp/Outlook Logging folder (for example, Outlook-*date-time*.etl).
3. Upload these files to the secure location provided during a support case so a Microsoft support engineer can convert and interpret them.

Because of this design, opening the .etl files in Event Viewer will typically show blank or unreadable event details; there is no supported way for customers to decode the Outlook ETW trace content themselves.

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References:

• How to enable global and advanced logging for Microsoft Outlook
• What is the Enable logging (troubleshooting) option?