Install Angular9 or latest version using PowerShell

For fresh start, Uninstall Node.js and npm

Uninstall node.js and npm using Windows Installer (msi)

To uninstall node.js and npm, Open Windows “Control Panel” -> “Uninstall a program”, select Node.js and click on uninstall to uninstaill both node.js and npm

Cleanup directories

After the uninstall, look for the following folders and delete them if exists
* Nodejs installed directory
* npm and npm-cache directories from %appdata% directory
* npmrc directory from user home directory ( C:\Users\{User} )

Now to re-install

Go to Node.js page and install current version

https://nodejs.org/en/download/current/

Check node and npm version;

node -v

npm -v

Open PowerShell in admin mode;

If you want to uninstall angular;

npm uninstall -g @angular/cli

npm cache clean –force

npm cache verify

Install a specific version of angular;

npm install -g @angular/cli@9.0.0

If you see this error, don’t worry. Angular is installed.

ng –v

You might get PowerShell digitally signed error; run these commands;

To check current execution policy, Get-ExecutionPolicy. A convenient method is to change the Execution policy using this cmdlet.

PS C:\ Set-ExecutionPolicy unrestricted

Press Y to confirm. The policy change is updated in the registry and remains this way, at least until you change it again. The unrestricted means loading absolutely all configuration files and running all scripts.

If you don’t want to unrestrict policy but to bypass the policy for current process, run this command;

Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass

Now running ng -v will work.

If you want to Install latest version of angular;

npm install -g angular/cli

This is the Location where angular package are stored;

C:\Users\[UserName]\AppData\Roaming\npm\node_modules\@angular\cli\bin\ng

Resources

https://windowsreport.com/powershell-not-digitally-signed/