VMware Live Site Recovery UI freezes when editing Protection Groups

Products

• VMware Live Recovery

Issue/Introduction

When attempting to edit a Protection Group in VMware Live Site Recovery, the vSphere Client user interface freezes and becomes unresponsive

 

• The browser tab may hang or show a "These pages aren't responding" warning
• The underlying SRM operation (e.g., adding or removing protection) completes successfully despite the UI freeze
• The problem persists even after increasing appliance resources (CPU/RAM) or modifying timeout settings

Environment

VLR 9.x

Cause

This behavior is caused by a browser layout engine failure, specifically a layout recalculation loop known as layout thrashing. This occurs when the browser's main thread becomes locked while attempting to calculate element dimensions. Common triggers include:

• Browser Zoom: Using a zoom level other than 100% creates fractional pixel dimensions that can trigger infinite recalculation loops
• Resource-Heavy Extensions: Organization-managed browsers with custom extensions or experimental AI features can cause memory leaks or thread locks
• Viewport Calculations: Specific viewport boundaries in the SRM protection group menu may conflict with standard browser rendering when certain extensions are active

Resolution

To resolve the UI freeze, perform the following troubleshooting steps:

1. Adjust Browser Zoom

Ensure the browser zoom level is set to exactly 100%. Fractional scaling from zoom levels like 110% or 125% is a primary trigger for layout thrashing

2. Disable Experimental Features and Extensions

• Deactivate any AI-based browser features or experimental modes
• Disable organization-managed extensions that monitor or modify web content in real-time
• Test the UI in an Incognito or Private window to confirm if third-party extensions are the cause

3. Implement Viewport Workaround

If the UI freezes, you can bypass the hang by changing the browser's viewport context:

• Press F12 (or Ctrl+Shift+I) to open the Developer Tools
• Dock the Developer Tools to the side of the browser window
• This action changes the viewport size and forces the browser to run layout processes in a separate debug context, which typically breaks the recalculation loop and restores UI functionality

4. Timeout Configuration (Optional)

While primarily is a browser issue, ensure your environment has adequate timeout values if you observe underlying network delays

Increase standard values in /opt/vmware/dr-client/lib/h5dr.properties to below:

• responseTimeout: 90000
• socketTimeout: 60000

For more details on UI responsiveness, refer to the Broadcom Tech Docs: The VMware Live Site Recovery user interface freezes and becomes unresponsive