What Manifest V3 Is and Why uBlock Origin Stops Working
Manifest V3 Chrome is the new extension framework that replaces Manifest V2 and changes how browser add-ons can block, inspect, and filter web traffic, which is why classic ad blockers such as uBlock Origin will no longer work the way users expect. Google has been phasing out Manifest V2 (MV2) since it announced the change years ago, but hidden compatibility flags and workarounds kept many older ad blockers alive. Those escape hatches are now being removed from Chromium, the engine behind Chrome, Edge, Opera, and other browsers. According to Chromium contributor Anton Bershanskiy, Chrome 149 is the last version with any MV2 compatibility. From Chrome 150 onward, MV2 is treated as dead code, which means uBlock Origin not working in Chrome is not a bug—it is the intended result of the Manifest V3 transition.
The Manifest V3 Timeline: Chrome 150, 151, and the End of MV2
Google’s extension kill switch arrives in two waves. Reporting cited by Lifehacker notes that Chrome 150 is expected to release on June 30, with Chrome 151 to follow sometime in July. Chrome 150 removes the kExtensionManifestV2Disabled flag from Chromium’s code, which locks out remaining tricks to keep MV2 extensions running. Chrome 151 goes further, stripping additional switches such as ExtensionManifestV2Unsupported, ExtensionManifestV2Availability, and AllowLegacyMV2Extensions that some users relied on to re-enable old add-ons. As Devlin Cronin explained in a Chromium commit, a giant company cannot support MV2 indefinitely because the unused code has become "unwanted technical debt" and a risk to reliability and security. Once these versions roll out, you will not be able to install MV2 extensions from the Chrome Web Store, and existing MV2 ad blockers will be disabled.
How Manifest V3 Changes Ad Blocking Capabilities
The core reason uBlock Origin is affected is that Manifest V3 changes how extensions can see and modify network traffic. Under Manifest V2, powerful ad blockers relied on the Web Request API to intercept and block connections in real time, applying large filter lists and custom rules. Manifest V3 replaces this with a more limited declarative rules system that moves control toward the browser. Google says this makes extensions more secure and easier to manage, but it reduces what ad blockers can do in Chrome. Lifehacker notes that the new limits “sever access to the Web Request API that ad blockers use to block traffic,” which makes fine-grained filtering harder. As a result, Manifest V3-compatible tools, including uBlock Origin Lite, cannot match the full functionality of the original uBlock Origin extension that ran under Manifest V2.
Browser Impact: Chrome, Edge, Opera, Firefox, and Others
Because the change happens in Chromium, it hits several browsers at once. Chrome, Microsoft Edge, and other Chromium-based browsers will lose support for Manifest V2 extensions in the same general window as Chrome 150 and 151. Even Opera, which once promised to keep MV2 "as long as it's technically reasonable," will be forced to drop it as Chromium removes MV2 support entirely. In contrast, Firefox runs on its own Gecko engine and has no plans to abandon MV2, making it the main option that can still run full-strength uBlock Origin. Privacy-focused browsers such as Brave offer built-in ad blocking that does not depend on Chrome extension support, and DuckDuckGo’s browser is another alternative with stronger tracking protection than stock Chrome.
Your Options Now: MV3 Ad Blockers, New Browsers, or Ads
If you find uBlock Origin not working after Chrome updates, you have three main choices. First, switch to Manifest V3-compatible ad blocker alternatives. Popular options include uBlock Origin Lite, Adblock, Adblock Plus, AdGuard, and Ghostery. These can block many ads, though their filtering power is more limited under MV3 rules. Second, move to a different browser: Firefox keeps full MV2 support, Brave has a built-in ad blocker, and DuckDuckGo offers strong privacy by design. Third, accept that Chrome will increasingly show ads and tracking scripts and use other tools—such as privacy settings, stricter cookie controls, and selective whitelisting—to manage your experience. Whatever you choose, review the data permissions of any extension you install so that your new ad blocker does not create fresh privacy problems.
