fails to load in Chrome 137.0.7151.56 when running npm run dev

[small-carbon]

Describe the bug

When running npm run dev to start development mode, the extension cannot be loaded in Chrome version 137.0.7151.56.
In earlier Chrome versions (e.g. 136.x), the same build works fine.

Reproduction

Run npm install
Run npm run dev
Open Chrome 137.0.7151.56 → Extensions → Load unpacked → Select dist folder
Observe that the extension fails to load (no errors shown / or show the errors here if any)

Steps to reproduce

No response

System Info

Chrome version: 137.0.7151.56

Used Package Manager

npm

Validations

• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[lorof]

Same issue on Chrome 137.0.7151.69 (macOS 15.5)

[aklinker1]

Chrome recently released a new version that broke WXT's dev mode. When the browser was started, your extension was not loaded automatically. This is because they removed the --load-extension flag.

✅ Upgrade to v0.20.7 if this is effecting you. It contains a hotfix that tells chrome to still accept this flag.

Or, if you can't/don't want to upgrade right now, just add this config to your project's wxt.config.ts file:

import { defineConfig } from 'wxt';

export default defineConfig({
  // v0.20 and above
  webExt: {
    chromiumArgs: ["--disable-features=DisableLoadExtensionCommandLineSwitch"],
  },
  // 0.19 and below
  runner: {
    chromiumArgs: ["--disable-features=DisableLoadExtensionCommandLineSwitch"],
  }
})

I am working on a long-term solution that doesn't rely on --load-extension, but that will come in the next major version (hopefully v1.0!): wxt#1700

[benjie91]

Still unable to work with the hotfix or upgrading wxt

[KyleRicardo]

I think it is not related to npm dev mode. Manually load unpacked extension built by wxt zip and then unzip, will popup an alert dialog saying "Could not load background script 'background.js'. Could not load manifest." Works fine in Chrome 136, broke in 137.

[aklinker1]

Still unable to work with the hotfix or upgrading wxt

@benjie91 What version of Chrome are you using?

[aklinker1]

I think it is not related to npm dev mode. Manually load unpacked extension built by wxt zip and then unzip, will popup an alert dialog saying "Could not load background script 'background.js'. Could not load manifest." Works fine in Chrome 136, broke in 137.

@KyleRicardo I need a reproduction to help you with this.

[chriswch]

Update
Turns out the following issue was caused by loading the unpacked extension directly from the WSL file system.
Once I copied the folder to a Windows path and loaded it from there, everything worked fine.

---

I just discovered this wonderful framework and tried initializing a project using pnpm, following the official tutorial:

pnpm dlx wxt@latest init .
pnpm i
pnpm dev

Since I’m using WSL, I loaded the unpacked extension manually in Chrome and got the same error:

Could not load background script 'background.js'.
Could not load manifest.

I came across this issue and tried the suggested solutions:

• Upgraded wxt to v0.20.7 (didn’t work)
• Added the config to wxt.config.ts (didn’t work)

my Chrome version is 137.0.7151.69.

[benjie91]

Still unable to work with the hotfix or upgrading wxt

@benjie91 What version of Chrome are you using?

It's v137. For now, I'm using the chromium browser which does not have this issue. Oh yes, I'm also using wsl and the browser is on window. Not the most ideal setup I know 🥲

[aklinker1]

Hmm, so WXT is generating a background script that v137 refuses to load, but v136 loads just fine.

Is anyone willing to share a reproduction with me? If not, there's not much I can do.

[yDog-1]

I was able to get it working by creating a symbolic link from my WSL development project directory to an arbitrary directory on the Windows side, and then loading .output/chrome-mv3-dev from that Windows directory into Chrome.

My environment is as follows:

• Chrome: 137.0.7151.69
• Bun: 1.2.14
• wxt: 0.20.7

[KyleRicardo]

My chrome v137 is in citrix environment. So I did a little digging, confirmed the root cause is the network path. Chrome 137 introduced a P0 level bug that will cause non-normalized root path cannot be parsed. They have fixed this bug in 138 and now merging it back to 137.

https://issues.chromium.org/issues/410059474

The changes in M137 will go out next week. Only 137 versions higher than 137.0.7151.81 will contain the fix.

[aklinker1]

Awesome, gonna close this then!