To Solve When I run ng new npm ERR! ERESOLVE unable to resolve dependency tree Error just Change "jasmine-core": "~3.7.0" to "jasmine-core": "~3.8.0" Open your package.json Simply edit the line that says "jasmine-core": "~3.7.0" to be "jasmine-core": "~3.8.0" then manually run npm install and it should succeed You should then be able to run ng serve --open from the same directory and have it run just fine.