Synthetic Recorder Extension blocked in incognito mode when ExtensionInstallForcelist is used

[ShahbazKhan]

Summary

This article explains how to troubleshoot and fix the issue where the Dynatrace Synthetic Recorder extension is blocked in Chrome or Microsoft Edge when using Incognito or InPrivate mode.

This issue is typically caused by browser policies such as ExtensionInstallForcelist, which prevent the extension from running in Incognito mode.

• Summary
• Problem
• Cause
• When to Use This Fix
• Best Practices
• What’s Next

Problem

When attempting to record a Synthetic Browser monitor (new or existing), the recorder opens an Incognito or InPrivate window, but the extension fails to load.

You may see an error such as:

• “This page has been blocked by Chrome”
• ERR_BLOCKED_BY_CLIENT

As a result:

• Recording does not start
• The page remains blocked indefinitely

Text from Image:

pbnfcaobikkbealhienfilklacghhgoi is blocked

This page has been blocked by Chrome

ERR_BLOCKED_BY_CLIENT

Cause

This behavior occurs when:

• The Dynatrace Synthetic Recorder extension is force-installed via policy
• The extension ID is configured in:
  • ExtensionInstallForcelist in browser policies (e.g., Registry / Group Policy)Value pbnfcaobikkbealhienfilklacghhgoi; https://clients2.google.com/service/update2/crx

This restriction specifically impacts:

• Incognito (Chrome)
• InPrivate (Edge)

Option 1 – Update browser policy (recommended)

If using ExtensionInstallForcelist, ensure developer tools are allowed.

Set the following policy:

HKLM\Software\Policies\Google\Chrome\
DeveloperToolsAvailability = 1

This enables the extension to function correctly in Incognito mode.

Option 2 – Disable Incognito for recording (workaround)

If policies cannot be changed, you can avoid Incognito mode entirely.

👉 See: How to record without Incognito

Key points:

• The Synthetic Recorder uses Incognito for a clean session
• Disabling it allows recording without policy restrictions
• This only affects local recording, not monitor execution

When to Use This Fix

Apply this solution if:

• Your organization enforces browser extensions via Group Policy
• Incognito mode is restricted or controlled
• The Synthetic Recorder extension appears blocked in Chrome or Edge

 

Best Practices

• ✅ Validate browser policies before installing the extension
• ✅ Avoid forcing extensions unless necessary
• ✅ Provide exceptions for DeveloperToolsAvailability where required
• ✅ Test recording both with and without Incognito

 

What’s Next

If the issue persists:

1. Confirm browser policy settings (Chrome/Edge)
2. Verify extension installation method
3. Test recording without Incognito
4. Collect error screenshots and browser logs

Then open a Dynatrace support chat with:

• Policy configuration details
• Extension setup method
• Exact error message

Related reading

📖  How to record or playback a Browser Monitor without Incognito mode  

📖  DeveloperToolsAvailability

📖  ExtensionInstallForcelist

[bill_smith]

What causes the extension to be added to this registry list?  Some anti-malware software?

[ShahbazKhan]

It’s mostly via Customer’s Group Policy to ensure uniformity across all devices