Why uBlock Origin stopped working in Chrome
Full uBlock Origin uses Manifest V2, the extension platform Chrome retired. This is a browser compatibility change; reinstalling the same extension cannot fix it.
Google’s timeline records the key changes:
- Chrome 138: Manifest V2 extensions were disabled for regular users, with the option to turn them back on removed in July 2025.
- Chrome 139 onward: Manifest V2 stopped working, including the enterprise policy exception.
- August 31, 2026: the remaining Manifest V2 extensions were removed from the Chrome Web Store.
Guides suggesting old Chrome flags or developer-mode installation no longer solve this. Keep Chrome updated and choose an extension it supports.
Choose Lite on Chrome or full uBO on Firefox
Stay on Chrome
Choose uBlock Origin Lite for everyday ad and tracker blocking. It is Raymond Hill’s separate Manifest V3 extension. Current desktop versions also support custom filters and external filter lists.
Use full uBlock Origin
Choose uBlock Origin on Firefox if you rely on its advanced controls or want its broader filtering capabilities. The project supports Firefox on desktop and Android.
Lite is not an automatic upgrade of your old extension. Its developer’s comparison explains why results can differ, particularly on sites that resist blocking.
Install uBlock Origin Lite on desktop Chrome
- Open the official Lite listing in Chrome. Check that it says uBlock Origin Lite, offered by Raymond Hill (gorhill).
- Select Add to Chrome, review the permissions, then confirm with Add extension.
- Open Chrome’s Extensions menu beside the address bar and pin Lite so its controls are easy to reach.
- Reload an ordinary website you visit and open Lite’s popup. Check that filtering is enabled for that site.
Install from a normal Chrome window: Google does not allow installation in Incognito or Guest mode. A work or school administrator may also restrict extensions.
Check filtering mode and website permissions
Start with Optimal, the intended default. Basic still blocks network requests, but does not apply cosmetic filters that hide page elements or scriptlet filters that adjust page behavior. Try Complete on a site if ad placeholders remain.
Optimal and Complete need permission to read and change website data for those extra filtering methods. You can grant access for individual sites or all sites. Restricting access means stronger filtering cannot run everywhere. The developer documents what each permission does.
If Lite is not working as expected
- It keeps returning to Basic. Open
chrome://extensions, find Lite, and select Details. Check its site access. A global Optimal or Complete setting requires access on all sites; limited access means limited coverage. - Ads or empty spaces remain. Check the mode on the affected site, try Complete, and reload. The official troubleshooting guide explains these mode and permission issues.
- A page breaks. Move Lite’s popup slider fully left to disable filtering for that site, then reload. If that fixes it, report the page using the popup’s chat icon. Restore filtering when the problem is resolved.
- It only fails in Incognito. Enable Allow in incognito in Lite’s Chrome extension details if you want it to run there.
Avoid running multiple content blockers together. When reporting a problem, include the affected URL and what failed. Use the project’s reporting instructions so maintainers receive the right details.
What about Chrome on Android or iPhone?
Chrome’s desktop extension installation does not install a blocker in mobile Chrome. On a phone, Add to Desktop queues installation for your computer. It does not enable Lite on that phone.
For Android, use Firefox with full uBlock Origin. For iPhone or iPad, see our Safari setup guide for Lite. A Safari extension does not block ads inside Chrome or other apps.