I had trouble logging in with ‘ionic login’ on my iMac. It said ‘Error logging in’ I followed the same instructions on my MacBook and it worked fine.
I then did Ionic --version
Macbook = 4.1.2
Imac = 1.7.12
I would really like to work on my iMac alongside my MacBook but the iMac is acting weird.
Node and NPM versions are:
Macbook
Node = 8.9.3
NPM = 5.6.0
Imac
Node = 8.12.0
NPM = 6.4.1
I ran ‘npm install -g ionic’ on both machines. Could somebody please tell me what’s wrong.
Thanks
Are you talking about the Ionic Dashboard/Creator ?
If not I am a bit confused because I don’t know what you mean by logging in. Do you mean your apps login ?
If you do not mean the Dashboard/Creator thing then I would bring your IMac NPM+Node version to the same status as your Macbook has. I would recommend you NVM for that its very easy to use and you can switch versions very quickly if you need to.
What you should do remove node and npm from your IMac. And install nvm.
GIT-Repo
(I’ve never installed nvm on Mac so I can’t really describe it how the nvm installation works I am sorry 
)
But after the installation of nvm I know the steps.
First restart your Terminal and type in:
nvm install 8.9.3
It will install the certain Node version (8.9.3).
Now type in:
nvm use 8.9.3
node -v
npm -v
It should display:
That you are using the version 8.9.3 now! Same as the certain npm version.
Since you might use a different npm version you have to install it by following
command.
npm install npm@5.6.0 -g
Ensure that you are running the right version now by typing in npm -v !
Thats it you can install different node versions aswell and switch around. 
Now do the simple installation of Ionic and you should be good to go!
Good luck! 
Full Documentation
Other Documentation for you to read.
It works just like it does on any other Unix, and thank you for your detailed response that does not suggest running npm under elevated privileges like so many comments I see here.
I am logging in by following the instructions found here. https://dashboard.ionicframework.com/welcome. I am right at the start of using Ionic so I followed the start guide and when I get to the point ‘Login to your Ionic Account from the CLI’ on the iMac I get ‘Error Login in’ This is only the 3rd step so clearly my iMac Terminal is not set up correctly I just can’t figure out why as it works fine on my macbook.
I have matched the node version numbers but surely that is not required so I’m thinking something else must be occurring.
Thanks for any help.
This is what I get when I use
sudo npm install -g ionic
npm WARN deprecated socks@1.1.10: If using 2.x branch, please upgrade to at least 2.1.6 to avoid a serious bug with socket data flow and an import issue introduced in 2.1.0
/Users/Paul/.nvm/versions/node/v5.3.0/bin/ionic -> /Users/Paul/.nvm/versions/node/v5.3.0/lib/node_modules/ionic/bin/ionic
+ ionic@4.1.2
updated 1 package in 6.935s
Then if I run ionic -v it still says 1.7.12. Also there is a deprecation warning which I’m not sure if that is causing a problem.
iMac:~ Paul$ ionic -v
1.7.12
Just an update. I have 2 logins on my iMac (I share it with my boss), I switched to the other login and run the ‘npm install -g ionic’ command and it now works. I can login using ‘ionic login’ . Strange but it is working now so I am happy.