How to Fix Ruby Bundle Gem Install Errors Fail on Windows

I’m writing this guide right after smashing my head on the desk for an hour and finally getting Blunder (the gem, not the feeling) to install on Windows. If you just typed

gem install blunder

and saw RubyGems explode with an ECONNREFUSED message, walk with me. I’ll show you exactly what happened on my machine, the quick proof-and-fix steps, and a little helper script I now keep in every project so this never bites me again.

The One Line Command That Broke

The minute I ran gem install blunder I got this:

:  Could not find a valid gem 'bundler' (>= 0), here is why:
    Unable to download data from https://rubygems.org/ -
    Errno::ECONNREFUSED: Failed to open TCP connection
    to 127.0.0.1:1080 (No connection could be made because the
    target machine actively refused it.)

What the Error

Why Did Ruby Gems Look at 127.0.0.1:1080?

RubyGems hunts for proxy settings in four spots, in this order:

1. Environment variables: HTTP_PROXY, HTTPS_PROXY, http_proxy, https_proxy
2. ~/.gemrc (or %USERPROFILE%\.gemrc on Windows)
3. Bundler settings (if you run inside bundle …)
4. Windows “Internet Options” proxy settings

Months ago I tested a Shadowsocks client that shoved

HTTP_PROXY=http://127.0.0.1:1080

into my user variables. The client is long gone, but the variable stayed behind. When RubyGems saw it, it dutifully tried that socket, found nothing, and threw ECONNREFUSED.

Fix The Error

Tip: If you really need a proxy later, add it to a PowerShell profile or a batch script you run manually instead of keeping it global.

The Tiny Helper Correct: gemdoctor.rb

I don’t like surprises, so I wrote a 40-line Ruby script that checks my proxy, pings RubyGems, and prints a friendly hint instead of a stack trace.

#!/usr/bin/env ruby
require "net/http"
require "uri"

RUBYGEMS_HOST = "https://rubygems.org"

def current_proxy
  ENV.values_at("https_proxy", "HTTPS_PROXY", "http_proxy", "HTTP_PROXY").compact.first
end

def rubygems_reachable?(proxy)
  uri  = URI.join(RUBYGEMS_HOST, "/specs.4.8.gz")
  host = proxy ? URI(proxy).host : nil
  port = proxy ? URI(proxy).port : nil
  http = Net::HTTP.new(uri.host, uri.port, host, port)
  http.use_ssl     = true
  http.open_timeout = 5
  http.read_timeout = 5
  http.start { |h| h.head(uri.request_uri).is_a?(Net::HTTPOK) }
rescue
  false
end

proxy = current_proxy
puts "GemDoctor: proxy = #{proxy || 'none'}"

if rubygems_reachable?(proxy)
  puts "✓ RubyGems reachable. You’re good:  gem install blunder"
else
  puts "✗ Can’t reach RubyGems."
  if proxy
    puts "  Proxy #{proxy} looks dead."
    puts "  Run:  setx HTTP_PROXY \"\"  (Windows) or  unset HTTP_PROXY (bash) and retry."
  else
    puts "  Check your firewall or VPN."
  end
end

How I Use It

ruby gemdoctor.rb

If the script prints a red “✗” I fix the proxy, rerun, and only then bother with gem install.

Explain it

• Auto-clear bad proxies
  Make gemdoctor.rb prompt “Clear proxy for me? (y/n)” and, on y, run ENV.delete plus setx HTTP_PROXY "".
• Pick the fastest mirror
  Add a loop that pings https://gems.ruby-china.com and https://mirrors.tuna.tsinghua.edu.cn/rubygems/, measures response time, and suggests the quickest source.
• Write a tiny log
  Append each run (timestamp, proxy, reachable) to gemdoctor.log so you can track flaky hotel Wi-Fi later.

You’ll practice Net::HTTP, environment tinkering, and Ruby’s simplest file I/O skills that pop up in real projects all the time.

Final Thought

Nine out of ten “gem can’t download” headaches on Windows trace back to a stale proxy entry, not a broken gem or a buggy Ruby install. Keep the checklist and gemdoctor.rb close, clear the variable, reset the source list, and watch installs fly. Your future self and every teammate who inherits your machine will thank you.