I wanted to run npm install from within my external hard drive as this is where i saved my code workspace. Windows 10 OS.

But I was getting the same error as the original post.None of the previous answers worked for me, I tried all of them:

1. uninstalling nodejs then re-installing
2. uninstalling nodejs then downgrading/installing a lower version of nodejs.
3. npm install -force
4. deleting the folders from C:\Users{YourUsername}\AppData\Roaming ... npm and npm-cache then re-installing.
5. npm cache clean --force
6. npm cache clean
7. npm install --g or npm install --global

What worked for me was this:

1. copy the folder from C:\Program Files\nodejs to D:\Program Files\nodejs
2. Then go to Control Panel\System and Security\System
3. Advanced System Settings
4. Environment Variables
5. System Variables
6. Double click Path
7. Add a new path
8. D:\Program Files\nodejs
9. Click ok
10. restart PC.
11. try npm install from within D: Drive