You have to be inside an angular-cli project in order to use the build command after reinstall of angular-cli

Same as John Pankowicz answer, but in my case I had to run

npm install -g @angular/cli@latest

for the versions to match.

npm uninstall -g angular-cli @angular/cli
npm cache clean
npm install -g @angular/cli

use sudo on Mac/Linux.

Ok, found it.

package.json must contain a dependency to angular-cli.

When I uninstalled my local angular-cli, npm also removed the dependency entry.

It worked in my case

sudo npm uninstall -g angular-cli @angular/cli
sudo npm cache clean --force
npm install npm@latest -g
sudo npm install -g @angular/cli

I had the same error message. But the cause and solution are slightly different. When I ran "ng -v" it showed different versions for angular-cli (1.0.0-beta.28.3) and @angular/cli (1.0.0-beta.31). I re-ran:

npm install -g @angular/cli

Now both show a version of 1.0.0-beta.31. The error message is gone and "ng serve" now works. (Yes - it was @angular/cli that I re-installed and the angular-cli version was updated.)

Use npm install angular-cli --save-dev

Execute following commands step by step :

sudo npm uninstall -g angular-cli @angular/cli

sudo npm cache clean

npm install npm@latest -g

sudo npm install -g @angular/cli

npm rebuild node-sass --force

This is what helped me when I found myself in the same problem:

npm uninstall -g angular-cli @angular/cli
npm cache clean --force
npm install -g @angular/cli@latest

npm uninstall -g angular-cli
npm uninstall --save angular-cli
npm uninstall -g @angular/cli
npm uninstall --save @angular/cli
npm cache clean
npm install --save-dev @angular/cli@latest

In my case (Mac OS X and previously used Angular 1.5 environment)

npm -g cache clean --force

npm cache clean --force

worked. (npm install -g @angular/cli@latest afterwards)

It works with npm install -g @angular/cli@latest for me.

This error comes when there's incompatibility between node version and angular/cli version. therefore use below command to update the cli version to latest

npm install -g @angular/cli@latest

npm uninstall -g angular-cli @angular/cli

npm cache clean --force

npm install -g @angular-cli/latest

I had tried similar commands and work for me but make sure you use them from the command prompt with administrator rights

It might be the problem with your version.

npm install -g @angular/cli@latest

The above run worked for me. Thanks!

I had the same issue - it turned out that i was using a deprecated angular-cli instead of @angular/cli. The latter was used by my dev team and it took me some time to notice that we were using a different versions of angular-cli.

Just include this in the package.json in devDependencies section

"angular-cli": "1.0.0-beta.25.5"

Not compulsory to install it if you have another vresion of cli installed globally.

I got this issue when I worked with angular2 & 4 at a time with different project. So angular4 - need angular-cli@latest and angular2 need angular-cli the above version.

I faced the same issue while running my project: I found out that if your project is using specific version of any thing in package.json find out that and install the specific version of that dependencies like for me, npm install @angular/cli@^4.0.0.

Dont forget of to use --force:

npm cache clean --force

I had the similar problem and nothing was working out but then I Followed below Steps and It worked for me. when I ran cmd as administrator it worked fine for me.

First run the Command Prompt as administrator ans. Create the new project.

If it still doesn't create the project, remove the folder and all it's files, and then run ng new <project name> followed by ng serve.

If nothing works just uninstall node and every other file related to it and follow the steps above

npm uninstall -g angular-cli 

npm install -g @angular/cli

That's it!

https://i.stack.imgur.com/J3qjR.jpg