If the new Firefox Nova interface isn’t for you, the reported full-disable workaround is an advanced preference: open about:config, search for browser.nova.enabled, and set it to false if the preference is available. Mozilla Support warns that changing advanced preferences can cause problems and that this one may eventually disappear, so safer appearance options include the Firefox Proton theme and Compact Mode.
What is Firefox Nova, and when did it arrive?
Mozilla calls the redesign Project Nova. Its desktop and mobile rollout began on September 29, 2026, alongside Firefox 157. Mozilla describes the update as softer tabs, rounder controls, refreshed icons and spacing, and a new color palette. Mozilla’s design overview and Firefox 157 launch post describe the changes and rollout.
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How to try the reported Nova disable preference
This is an advanced workaround reported in a Mozilla Support discussion, not a documented, permanent opt-out control. Confirm that the preference exists in your installed Firefox version before changing it.
- Enter
about:configin Firefox’s address bar and open the advanced configuration page. - Search for
browser.nova.enabled. - If it appears, change its value to
false. - Check whether the interface changes. A Firefox Support user reported that the usual design elements returned after changing the preference.
Mozilla Support moderator Paul cautioned: “Changing Firefox preferences from the about:config page can sometimes break Firefox or cause strange behavior.” He also advised against using the preference to reverse Nova because it could be removed over time. No removal date is established, so the setting may not be present or work in every version. Read the Mozilla Support discussion.
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Safer ways to make Firefox look more familiar
Use the Firefox Proton theme
Mozilla’s Add-ons Community Blog says the Firefox Proton theme is featured in Add-ons Manager for people who prefer the previous look. It is a theme, not a complete rollback or a switch that disables Nova. See Mozilla’s Firefox 157 Add-ons Community post.
Turn on Compact Mode
Compact Mode reduces the size of tabs and the toolbar. Mozilla also describes an auto-compact option for smaller screens. It changes the amount of space Firefox’s controls take up rather than restoring the entire previous interface.
Adjust themes and the New Tab page
Firefox’s theme picker and New Tab customization provide additional ways to change the browser’s appearance. These controls can help if the main issue is color or the New Tab page, without changing an advanced preference. Mozilla outlines them in its Firefox 157 launch post.
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Quick Recap
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Which option should you choose?
| Option | What it changes | Trade-off |
|---|---|---|
browser.nova.enabled set to false |
Reported as disabling Nova and restoring previous design elements. | Advanced, may cause unexpected behavior, and Mozilla says the preference may eventually be removed. |
| Firefox Proton theme | Provides a familiar theme option through Add-ons Manager. | Changes the theme; it does not fully disable Nova. |
| Compact Mode | Reduces tab and toolbar size. | Changes control size, not the full interface design. |
| Theme picker and New Tab customization | Adjusts other parts of Firefox’s appearance. | These are narrower customizations, not a complete rollback. |
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