Quick Summary
Google Chrome is phasing out support for MV2 extensions like uBlock Origin. But you can still install them by enabling a Chrome flag ‘Allow legacy extension manifest versions’ and manually loading the extension.
I am a huge fan of uBlock Origin and have been using it from the time it was available as a project on GitHub. But a year ago, Google announced it would deprecate the support for manifest V2 — a specification used by browser extensions in Chrome and other Chromium-based browsers. uBlock Origin also uses the same manifest version.
Google announced that a new V3 manifest would be used as a standard moving forward, which caused many extensions like uBlock, HTTPS Everywhere, Privacy Badger, AdBlockers, and others to update to the V3 Manifest or close their service due to V3 restrictions. Below is a simple table showing the difference between Mv2 and Mv3.
| Feature | Manifest V2 | Manifest V3 |
|---|---|---|
| Speed | Slower, uses more memory | Faster and more efficient |
| Security | Less secure | Stronger privacy and security |
| Ad Blocking | More powerful blockers are possible | Some blockers may be limited |
| Battery Use | Higher | Lower (better for laptops) |
| Support Status | Being phased out | Future-ready and required |
A few months ago, many users reported that the uBlock Origin “Add to Chrome” button was greyed out and the extension was being forcibly turned off—I found a solution using Chrome Dev Tools to reinstall the extension on the browser.
Recently, as of 11 July 2025, users reported on my YouTube channel that the extension is again being turned off, and when trying to re-add it to Chrome, they are seeing an error “Cannot install extension because it has unsupported manifest version”. And guess what, I found a solution for this as well, although temporary, as the upcoming Chrome 139 update would permanently phase out the dying legacy support for V2 manifest extensions.
Below is a simple step-by-step guide that you can use to install the unsupported manifest Chrome extensions on your browser.
You can watch this YouTube video I made on the same issue, or head over to the steps that are simple and provide a quick fix.
Steps to Fix Unsupported Manifest Version on Google Chrome
Step-by-step tutorial to fix the Chrome extension unsupported manifest version error and install uBlock Origin with Chrome Flags.
- In the Chrome Omni box, type chrome://flags and hit Enter.
- This opens experimental Chrome features called Flags.
- Now, here in the search box, type Manifest.
- Look for a flag named Allow legacy extension manifest versions. This flag will allow you to install V2 manifest version extensions.
- Next to the flag, click on the drop-down menu, select Enabled, and click Relaunch.
- Once the browser restarts, go to the Chrome extension manager page by entering chrome://extensions.
- In a Chrome extension manager page, make sure to enable Developer mode on the top right.
- Now open the Ublock Origin GitHub release page—under assets, click on Ublock Origin Chromium zip to download the zip file.
- Extract the zip file, and you will see the uBlock Origin folder with all necessary files and data.
- On the Chrome extension page, click on Load Unpacked and select the extracted folder.
- Boom! The extension is installed on your Chrome browser and added to the toolbar.
Not all the extensions are readily available as a *.zip file. In such a case, we can directly download the *.crx file. Extract the downloaded file using the CRX extractor available online. The CRX file will be converted into a ZIP file, and then we can extract the folder from the ZIP file— install it as load unpacked.
Frequently Asked Questions (F.A.Q.)
1. What is Manifest V3?
Manifest V3 is an extension rule that sets a standard for how an extension will work—most modern extensions on the Chromium browser are running with MV3 code.
2. Can I use MV2 extensions on Google Chrome?
No! Google has stopped support for extensions that are using the V2 manifest, with extensions being taken down from the Chrome web store and extensions being automatically turned off for most users.
3. What is the difference between the MV2 and MV3 extensions?
MV2 extensions could fully read and change website data when the page is loading, while MV3 extensions have limited event-based access.
4. Will all browsers in the future switch to MV3?
Firefox said it will support V2 along with the V3 manifest. While most of the Chromium-based browsers will soon switch to MV3.
5. Any Chromium browser that supports MV2?
Brave still supports MV2 and plans to keep the support until there are no technical limitations due to the Blink engine.
6. Can I use uBlock Origin on Chrome?
You cannot use uBlock Origin on Chrome, but you can install it on Firefox or other Chromium-based browsers like Brave and Vivaldi.
Conclusion
Though the life of uBlock Origin is coming to an end, especially on Chrome, the ventilator support for the dying extension is what keeps it alive. With a Chrome flag, you can keep the legacy Manifest V2 functional for now and install the unsupported extensions on the Chrome browser.
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