Composer install dependency error drupal/drupal dev-master I'm managing my site dependencies via composer, most of the times works really well. Now I installed my site on a new server, using the exact same code-base as before (but with composer 1.8.0 instead of 1.7.x as before though). On running composer install I get the following error:


  
  don't install drupal/core 8.6.4|remove drupal/drupal dev-master
  remove drupal/drupal dev-master|remove drupal/core 8.6.4
  Installation request for drupal/drupal dev-master -> satisfiable by drupal/drupal[dev-master].
  Installation request for drupal/core 8.6.4 -> satisfiable by drupal/core[8.6.4].
  


Usually I can solve these sorts of errors but this time I'm having a hard time. What's the meaning of drupal/drupal dev-master, because usually you do not specify this anywhere directly?
I ran into the same issue. My issue was related to upgrading to a new Drupal core minor version (ex: 8.6 to 8.7). If that's not the case for you, then my steps may be unnecessary.

I was able to resolve it by removing the core directory of Drupal. Then run composer update drupal/core --with-dependencies. I believe the issue stems from the core/composer.lock file having conflicts with what you are trying to install.