I have recently added a new root source css file for magento storefront by putting it in default_head_blocks.xml throught below statement.

<css src="css/custom.css"/>

Now I ran upgrade command

php bin/magento setup:upgrade

I am having the same custom.less file at below path of my custom theme.


When I now try to run deploy command Magento is giving me an error

pub/static/frontend/myvendor/mytheme/en_US/css/custom.css): failed to open stream: No such file or directory

I don't know if this is a version issue or not but I already tried signing off static files from backend by setting

store>configuration>advanced>Developer>Static File Setting>Sign Static Files to No

as well as trying to run the command again with admin rights.

Still, the error persists.

  • did you create custom.css file also at the location of pp/design/frontend/myvendor/mytheme/web/css ? Commented Sep 19, 2018 at 5:55
  • read this block for batter understanding how less css work in M2 webkul.com/blog/use-less-magento-2-template-modules Commented Sep 19, 2018 at 6:27
  • Yes, I have created .less file at that location. Commented Sep 19, 2018 at 16:31
  • If I create blank .less file, magento is giving an error. Is it normal behavior of static content deploy? Commented Sep 19, 2018 at 16:34

1 Answer 1


This error was actually created as custom.less file was blank and therefore magento was not generating custom.css file from it.

I don't know if it is bug or not as blank custom.css file should be generated from respective blank custom.less file.

Adding some css rules to it solves this issue.

  • Could you please explain more about this. what kind of css rules are required ?
    – chanchal
    Commented May 1, 2019 at 4:46
  • Add any css selector with properties in it. In short, file should not be blank. Commented May 1, 2019 at 4:56

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