This night I had a frustrating problem. I bought RubyMine the other day for usage when learning Rails.

After 20 minutes I was ready to tear my hair out. No matter what I tried RubyMine kept saying that I needed to attach the rails gem. It also couldn’t execute tests since test-unit was not attached and so on. Gem install worked fine from the command prompt and bundle install did was working too.

Ended up being that I had set up both GEM_PATH and GEM_HOME last week when installing rails (I had trouble with windows permissions..). They pointed to different (non-standard) directories.. Setting up only GEM_PATH to the correct path worked wonders. For me this was ruby install dir\lib\ruby\gems.

E.g:

I:\Ruby192\lib\ruby\gems

After that life was fine again and the cortisol levels were dropping. :-)

TLDR: don’t change defaults on a poor development platform.