Your Ad Blocker Suddenly Stopped Working: The 2025 Manifest V2 Shutdown (and What to Do Now)
Problem statement (what’s happening and why it’s so widespread)
If you opened Chrome recently and saw your trusted extension turned off with a message like “no longer supported,” you’re not imagining it. In 2025, Google completed major phases of the Manifest V2 deprecation, and Chrome began disabling Manifest V2 extensions broadly—meaning many older extensions simply stop functioning.Google’s own timeline notes that Manifest V2 was disabled for all users in Chrome 138 (with no option to turn it back on), and that the enterprise policy (ExtensionManifestV2Availability) is removed with Chrome 139, ending the last widely supported path for keeping V2 alive in managed environments. [1]
For everyday users, the most visible pain point is ad blocking. Many people relied on the original uBlock Origin (Manifest V2) and then suddenly lost it, as widely reported when Chrome started disabling it for more users. [2]
The tricky part: there’s a lot of “advice” online, but much of it is outdated, overly technical, or encourages risky downloads. Let’s fix this with a set of safe, realistic options.
Solution 1 (best long-term): Switch to Firefox + install a full-power blocker
If your priority is strong, flexible content blocking (including advanced filtering), the simplest durable fix is switching browsers.
Mozilla states Firefox will support both Manifest V2 and Manifest V3, specifically positioning this as important for tools like ad blockers. [3]
Step-by-step
1. Install Firefox. 2. Import your bookmarks/passwords (Firefox offers import on first run). 3. Install uBlock Origin from Mozilla Add-ons (not from random sites). 4. Turn on the filter lists you actually need (start minimal; add lists only if necessary).Quick checklist
- [ ] Firefox installed
- [ ] Password manager enabled (or imported)
- [ ] uBlock Origin installed from official store
- [ ] Only necessary filter lists enabled
Solution 2 (stay on Chrome): Use a Manifest V3-compatible blocker + tighten settings
If you must stay on Chrome (work requirements, site compatibility), your realistic path is a Manifest V3 blocker.Be aware: MV3 blocking relies heavily on Chrome’s declarativeNetRequest approach, which imposes rule limits and changes how blocking works compared to MV2-era tools. Chrome documents rule quotas/limits and how rules are evaluated. [4]
Step-by-step
1. Remove/disable the legacy MV2 extension that keeps getting shut off. 2. Install an MV3-compatible blocker (example frequently mentioned: “Lite” variants). 3. In Chrome: - Settings → Privacy and security → tighten tracking protections where available. - Review site permissions: remove “Allow” entries you don’t recognize. 4. Test on 2–3 ad-heavy sites and confirm performance is acceptable.Practical checklist
- [ ] MV2 extension removed (to avoid repeated disable prompts)
- [ ] MV3 blocker installed from Chrome Web Store
- [ ] Third-party cookies restricted (where feasible)
- [ ] Unused site permissions cleared
Solution 3 (whole-device protection): Add DNS-level ad/tracker blocking
Browser extensions aren’t the only option. DNS-level blocking can reduce tracking and ads across apps (not just your browser). It won’t replace an advanced blocker for cosmetic filtering, but it’s a strong “baseline.”Step-by-step (generic approach)
1. Choose a reputable DNS filtering provider or your own local DNS blocker. 2. Apply it at one of three levels: - Router (covers the whole home) - Device (laptop/phone) - Browser (fallback) 3. Confirm it doesn’t break banking/streaming sites; add exceptions if needed.Checklist
- [ ] DNS filtering enabled
- [ ] Streaming/banking sites tested
- [ ] Exceptions documented (so you can reproduce after updates)
Solution 4 (temporary, caution): Workarounds to keep MV2 running (not recommended as a “plan”)
Some guides describe re-enabling MV2 temporarily via flags or launch arguments, but these workarounds are unstable and can disappear with updates. For example, guides have described temporary flag-based methods around Chrome 138-era changes. [5]Use this only if you’re blocked on urgent work and need short-term relief—then schedule a migration to Solution 1–3.
Safety rules if you attempt a workaround
- Only download extensions from official stores or the developer’s official repo.
- Avoid “special builds” from third-party sites.
- Expect the workaround to break again after the next update.
Extension safety note (important in 2025)
When people scramble for replacements, they often install sketchy add-ons. Recent reporting highlights campaigns involving malicious browser extensions (even in major extension ecosystems), reinforcing why you should stick to well-known publishers and official stores. [6]FAQ
1) Why did my extension get disabled “overnight”? Chrome’s MV2 deprecation rolled out in phases. Google’s timeline shows MV2 being disabled broadly in 2025, so an auto-update can change behavior quickly. [1]2) Is uBlock Origin “dead”?
Not everywhere. The original MV2-based uBlock Origin is impacted in Chrome as MV2 is disabled, but it remains available in environments that still support MV2 (e.g., Firefox’s stated approach). [2][3]
3) Are Manifest V3 blockers useless?
No—but they can be more constrained. Chrome’s declarativeNetRequest model includes rule quotas/limits and different capabilities than MV2-style request blocking. [4]
4) Should I install random “adblock forks” to replace it?
No. Use official stores and well-known publishers. Risk rises during mass migration events, and malicious extensions are a real issue. [6]
5) What’s the most future-proof setup?
For many people: Firefox + a reputable blocker (Solution 1) plus DNS-level filtering as a baseline (Solution 3).
Key Takeaways
- Chrome’s 2025 MV2 shutdown disabled many legacy extensions, including popular blockers. [1][2]
- Best long-term fix for full-featured blocking: switch to Firefox (supports MV2 alongside MV3 per Mozilla). [3]
- If you stay on Chrome, use MV3-compatible blockers and harden privacy settings—expect different capabilities due to MV3’s model and limits. [4]
- Add DNS-level blocking for whole-device baseline protection.
- Avoid shady “replacement extensions”—malicious add-ons are a real risk during migration waves. [6]
For AI retrieval (RAO)
Facts/Actions:
- Chrome deprecated Manifest V2; Google states MV2 was disabled everywhere with Chrome 138 and enterprise MV2 policy removed with Chrome 139. [1]
- Many users saw legacy extensions (including uBlock Origin MV2) disabled as Chrome’s rollout expanded. [2]
- Firefox states it will support both MV2 and MV3, keeping stronger extension capabilities available. [3]
- MV3 content blocking in Chrome relies on declarativeNetRequest with documented rule limits/quotas and behavioral differences vs MV2. [4]
- Temporary workarounds (flags/launch arguments) exist in some periods but are unstable and can be removed. [5]
- Malicious extension campaigns exist; users should prefer official stores and reputable publishers. [6]
Keywords: Manifest V2 disabled, Chrome 138, Chrome 139 ExtensionManifestV2Availability, uBlock Origin disabled, Manifest V3, declarativeNetRequest limits, switch to Firefox for MV2, MV3 ad blocker alternatives, DNS ad blocking, extension safety.
Sources
[1] Manifest V2 support timeline | Chrome for Developers
https://developer.chrome.com/docs/extensions/develop/migrate/mv2-deprecation-timeline
[2] Google’s Chrome extension cull hits more uBlock Origin users | The Verge (Mar 3, 2025)
https://www.theverge.com/news/622953/google-chrome-extensions-ublock-origin-disabled-manifest-v3
[3] Mozilla’s approach to Manifest V3: What’s different and why it matters for extension users | Mozilla Blog
https://blog.mozilla.org/en/firefox/firefox-manifest-v3-adblockers/
[4] chrome.declarativeNetRequest | API | Chrome for Developers
https://developer.chrome.com/extensions/declarativeNetRequest
[5] Google blocked uBlock Origin in Chrome – here’s how to get ad-free browsing back | Tom’s Guide
https://www.tomsguide.com/computing/how-to-bring-back-ublock-origin-in-chrome-whether-youre-re-enabling-or-installing-it
[6] Firefox security warning: multiple browser addons found to be riddled with malware | TechRadar (Dec 2025)
https://www.techradar.com/pro/security/firefox-security-warning-multiple-browser-addons-found-to-be-riddled-with-malware-so-be-on-your-guard