Session Windowsupdatetracelog Failed To Start With The Following Error 0xc0000035 Repack -

Fix: “Session WindowsUpdateTraceLog Failed to Start with Error 0xc0000035” (Repack Guide)

If you are a Windows system administrator, a PC technician, or an advanced user building custom images (repacks), you may have encountered a cryptic error message while inspecting the Event Viewer or during a sysprep process:

“Session ‘WindowsUpdateTraceLog’ failed to start with the following error 0xc0000035.”

This error often appears alongside the keyword “repack” — referring to repackaged Windows installations, custom ISOs, or modified system images. It is frustrating because it doesn’t always crash the system visibly, but it can lead to update failures, performance degradation, and Sysprep errors. This error often appears alongside the keyword “repack”

This article will explain exactly what this error means, why it happens during repacking, and how to resolve it permanently.

“Failed to start with the following error 0xc0000035”

Error code 0xc0000035 translates to STATUS_OBJECT_NAME_COLLISION. In simple terms: An object (file, registry key, or session) with the same name already exists. Press Win + X

So the message means: Windows tried to start the ETW session for logging Windows Updates, but another session or system component already holds that resource.

“Repack”

In the context of this error, “repack” refers to a custom Windows image — for example, a modified .wim or .esd file created with tools like NTLite, MSMG Toolkit, or DISM. Repacking often involves removing components, integrating updates, or altering services. This process commonly triggers the error. why it happens during repacking

Step 1: Verify the Error in Event Viewer (for clarity)

1. Press Win + X, select Event Viewer.
2. Navigate to:
   Applications and Services Logs > Microsoft > Windows > WindowsUpdateClient > Operational
3. Look for Event ID 2 or 1001 with the text:
   “Session ‘WindowsUpdateTraceLog’ failed to start with the following error 0xc0000035.”

Solution 1: Run the System File Checker (SFC) Scan

The SFC scan checks and repairs corrupted system files.

1. Open Command Prompt as an administrator.
2. Type sfc /scannow and press Enter.
3. Wait for the scan to complete.