What is CLS by operating system
CLS by operating system shows Cumulative Layout Shift (CLS) values across different operating systems (e.g., Windows, macOS, Linux). This lens helps you identify which OS environments may be contributing to unexpected layout shifts during page load.
The list includes only operating systems that generated traffic to your website during the selected period.
A common reason for poor CLS on certain operating systems is the wide range of device configurations and screen behaviors — especially on platforms like Windows, where hardware and browser combinations vary widely.
Healthy CLS by operating system sample
A healthy CLS by operating system lens shows all green — meaning users across different systems are experiencing a stable visual load.
Some platforms may perform slightly better than others, but as long as there’s no yellow or red, your layout is considered stable across environments.
Unhealthy CLS by operating system sample
In the example below, macOS shows the worst CLS values. This can lead to visual instability for a significant portion of your users — especially those on Safari or Chromium-based browsers running on Apple hardware.
Common causes of layout shifts on macOS include:
Late-loading system fonts or custom web fonts that reflow text.
Scrollbars behaving differently on macOS, especially with overlay scroll.
Fixed or sticky elements that behave inconsistently across macOS browser versions.
Design elements optimized for Windows or mobile that don’t adapt well to macOS resolutions.
Even small layout shifts can feel jarring on macOS, where users expect a smooth, polished experience. Poor CLS here can increase bounce rates and reduce perceived quality.
Resolving unhealthy CLS by operating system
Go-to action plan to resolve an unhealthy CLS by operating system:
Ask Uxi to analyze your CLS by operating system values and suggest improvements
Use Filters to focus on the affected OS and correlate with other CLS lenses (e.g., page, device, or user type).
Simulate CLS of the suspected lens to see if fixing it will resolve the CLS by operating system. If yes, this is where the resolution focus should be.
Use an automated CLS optimization tool like Navigation AI to improve your CLS by operating system values
Once you’ve improved CLS, set an alert to be the first to know if it starts worsening again.
Try it yourself
Discover how your website performs with real user data.