Command

build

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

My usecase is to include an unprocessed (in terms of css style preprocesser) "external.css" file in index.html. so i modified index.html and added a "dummy" external.css and put a file "external.css" in "public" folder

During ng build the following warning occurs:
▲さんかく [WARNING] Unable to locate stylesheet: C:\external.css

It seems that it's only a misleading warning as the external.css file is put as expected under dist folder after ng build.

Minimal Reproduction

A reproduction of the issue can be found here:

https://github.com/dd-frank/external

Exception or Error

During ng build the following warning occurs:
`[Warning] Unable to locate stylesheet: C:\external.css`

Your Environment

Angular CLI: 20.2.0
Node: 22.17.1
Package Manager: npm 10.9.2
OS: win32 x64
Angular: 20.2.0
... build, cli, common, compiler, compiler-cli, core, forms
... platform-browser, router
Package Version
------------------------------------
@angular-devkit/architect 0.2002.0
@angular-devkit/core 20.2.0
@angular-devkit/schematics 20.2.0
@schematics/angular 20.2.0
rxjs 7.8.2
typescript 5.9.2
zone.js 0.15.1

Anything else relevant?

No response