Chrome ad blockers stop working in Chrome 150: what to do

Chrome 150, shipping June 30, removes the last internal flag that allowed determined users to keep Manifest V2 ad blockers alive in Chrome. Chrome 151, due in July, clears out the remaining residue. For Chrome users running mainstream MV3 blockers, neither update changes anything. For users who depended on the full version of uBlock Origin, Chrome 151 closes the final workarounds.

The Manifest V2 deprecation itself completed last year. What ends now are the escape hatches.

How we got here

Google stopped accepting new MV2 extensions to the Chrome Web Store in January 2022, then began disabling existing MV2 extensions in Chrome Stable in October 2024, per the Google Chromium blog. Chrome 138 completed that transition last year, making the full version of uBlock Origin officially unavailable to standard Chrome users, heise reported earlier this month.

But the formal deprecation left scaffolding behind. Enterprise IT departments had used the ExtensionManifestV2Availability policy, configurable via Windows group policies or registry entries, to keep MV2 extensions running past the shutdown date. Chrome 138 was the last version to honor that policy; Chrome 139 removed it. Enterprises had been given until June 2025 to migrate, heise explains. Power users, meanwhile, had kept older extensions alive through a handful of internal flags that Chrome hadn't yet pulled. Chrome 150 and 151 pull them.

By Google's own count, more than 85% of actively maintained extensions in the Chrome Web Store had migrated to MV3 when the phase-out began in earnest, including MV3 versions of all the top content-filtering tools, per the Google Chromium blog. From Google's perspective, what's being removed now is dead code.

Why Chrome ad blockers stop working after Chrome 150 and 151

Chrome 150 removes the kExtensionManifestV2Disabled flag. A Google engineer in the W3C WebExtensions Community Group described it as dead code, since MV2 extensions are no longer permitted in any supported Chrome version, 9to5Google reports today. That flag had been the primary technical lever users exploited to force older extensions to keep running after the formal shutdown. Removing it cuts off the most accessible workaround.

Chrome 151 follows by removing three additional flags: ExtensionManifestV2Unsupported, ExtensionManifestV2Availability, and AllowLegacyMV2Extensions, eliminating every remaining internal mechanism tied to the old platform, per heise and 9to5Google. One path technically persists after Chrome 150: a DevTools-based method that requires manually patching page elements each session. It isn't a realistic option for daily browsing, 9to5Google notes.

Google's stated rationale is maintenance burden, not policy. A Google engineer confirmed the team can no longer sustain MV2 infrastructure given "the complexity and tech debt, as well as the security risks it entails," citing a recent uptick in MV2-specific bugs as a concrete driver, The Verge reports today. The core architectural change driving all of this is the replacement of the real-time webRequest API with the predefined-ruleset declarativeNetRequest model, which Google positions as a security, stability, and performance improvement, according to heise.

What this means, depending on which blocker you use

This is where the story splits into two distinct experiences.

If you use a mainstream MV3 blocker AdGuard, Adblock Plus, or most others:

Chrome 150 and 151 change nothing. These extensions already run on MV3 and will continue operating normally.

The evidence on MV3 blocking performance is more reassuring than early alarm suggested. A large-scale study across 924 websites found no statistically significant difference in ad-blocking effectiveness between MV3 and MV2 blockers. MV3 versions actually blocked approximately 1.8 more trackers per site on average, according to an arXiv preprint published last year. The study compared mainstream blockers including Adblock Plus, AdGuard, and uBlock across standard websites using screenshot-based outcomes; it does not cover advanced filtering scenarios. Within those limits, the results hold up.

One concern that didn't materialize: running multiple MV3 blockers simultaneously, given MV3's shared 330,000-rule ceiling across all installed extensions, did not reduce ad-blocking performance. In some configurations it improved tracker blocking, the same research found.

If you use uBlock Origin Full:

The classic version of uBlock Origin is maintained as an MV2 extension. A fully functional MV3 port does not exist. For Chromium-based browsers, the project points users to uBlock Origin Lite, a deliberately reduced variant that hits declarativeNetRequest rule limits and lacks the dynamic filtering capabilities that make the full version effective against anti-adblock scripts and complex custom filter lists, heise explains. MV3 caps individual extensions at 30,000 blocking rules, with the 330,000-rule collective ceiling applying across all installed extensions constraints that uBlock Origin Lite already runs into under heavy use, per the arXiv study.

Casual ad blocking and tracker interception hold up in MV3. Dynamic filtering, custom rule injection, cosmetic filtering, and anti-anti-adblock behavior do not have a Chrome home. For users who rely on those capabilities, Chrome 151 removes the last known workarounds.

Firefox and Brave are the real alternatives for Manifest V2 ad blockers

Google acknowledged that other browsers can keep supporting MV2 if they choose, The Verge reports. Several have. For uBlock Origin Full users, two offer meaningful and well-defined support.

Firefox is the lower-friction switch for most users. Mozilla supports MV2 and MV3 simultaneously, retains the blocking webRequest API, and has no plans to remove it. The full version of uBlock Origin runs on Firefox without modification. Firefox extensions are entirely unaffected by anything Chrome does, heise confirms.

Brave goes further. The browser force-enables MV2 support at the engine level and directly hosts four extensions, including uBlock Origin, on its own infrastructure, decoupled from the Chrome Web Store, heise reports. For users who want to stay on a Chromium-based engine while keeping MV2 capability, Brave is the clearest option.

Two other browsers are worth a quick note. Opera has stated it intends to support existing MV2 extensions "for as long as possible," though no concrete commitment backs that up. Microsoft has documented the end of MV2 for Edge but left the timeline open, making it an unreliable choice for anyone who needs guaranteed MV2 support, per heise.

What to do before Chrome 150 ships June 30

For users running AdGuard, Adblock Plus, or any other MV3 blocker, no action is needed. The arXiv study found no meaningful performance gap across 924 sites, per the preprint, and the Chrome 150 and 151 updates don't touch that.

For uBlock Origin Full users, the window for a managed transition is short. Chrome 150 ships June 30; Chrome 151 follows in July. Firefox offers the simplest path: install the browser, carry over bookmarks, and uBlock Origin Full runs exactly as before. Brave suits users who want to stay on a Chromium engine without giving up MV2 support. uBlock Origin Lite remains available for Chrome, but it is a deliberate step down in capability, heise confirms.

Google has made clear this direction is final. The flags coming down in Chrome 150 and 151 aren't the beginning of a negotiation; they're the last of the infrastructure.