diff --git a/CHANGELOG.md b/CHANGELOG.md
index fa5ff943..f161e1b7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Referring to an undefined platform no longer causes a crash; it's now a helpful error message
 - A copy/paste error that prevented compiler warning flags from being supplied has been fixed, via jgfoster
 - RSpec was not communicating compile errors from unit test executables that failed to build. Now it does, via jgfoster
+- Windows paths now avoid picking up backslashes, for proper equality comparisons
 
 ### Security
 
diff --git a/lib/arduino_ci/arduino_backend.rb b/lib/arduino_ci/arduino_backend.rb
index 4e04f5b3..cb3e4238 100644
--- a/lib/arduino_ci/arduino_backend.rb
+++ b/lib/arduino_ci/arduino_backend.rb
@@ -90,7 +90,9 @@ def config_dump
 
     # @return [String] the path to the Arduino libraries directory
     def lib_dir
-      Pathname.new(config_dump["directories"]["user"]) + "libraries"
+      user_dir_raw = config_dump["directories"]["user"]
+      user_dir = OS.windows? ? Host.windows_to_pathname(user_dir_raw) : user_dir_raw
+      Pathname.new(user_dir) + "libraries"
     end
 
     # Board manager URLs
diff --git a/lib/arduino_ci/arduino_downloader.rb b/lib/arduino_ci/arduino_downloader.rb
index 2acdf30c..c3081f7d 100644
--- a/lib/arduino_ci/arduino_downloader.rb
+++ b/lib/arduino_ci/arduino_downloader.rb
@@ -43,7 +43,7 @@ def self.autolocated_executable
     # The executable Arduino file in an existing installation, or nil
     # @return [Pathname]
     def self.existing_executable
-      self.must_implement(__method__)
+      Host.which("arduino-cli")
     end
 
     # The local file (dir) name of the desired IDE package (zip/tar/etc)
diff --git a/lib/arduino_ci/arduino_downloader_linux.rb b/lib/arduino_ci/arduino_downloader_linux.rb
index 487273d1..8eb787eb 100644
--- a/lib/arduino_ci/arduino_downloader_linux.rb
+++ b/lib/arduino_ci/arduino_downloader_linux.rb
@@ -17,12 +17,6 @@ def self.extracted_file
       "arduino-cli"
     end
 
-    # The executable Arduino file in an existing installation, or nil
-    # @return [string]
-    def self.existing_executable
-      Host.which("arduino-cli")
-    end
-
     # Make any preparations or run any checks prior to making changes
     # @return [string] Error message, or nil if success
     def prepare
diff --git a/lib/arduino_ci/arduino_downloader_osx.rb b/lib/arduino_ci/arduino_downloader_osx.rb
index 89890599..9e77505b 100644
--- a/lib/arduino_ci/arduino_downloader_osx.rb
+++ b/lib/arduino_ci/arduino_downloader_osx.rb
@@ -17,12 +17,6 @@ def self.extracted_file
       "arduino-cli"
     end
 
-    # The executable Arduino file in an existing installation, or nil
-    # @return [string]
-    def self.existing_executable
-      Host.which("arduino-cli")
-    end
-
     # Make any preparations or run any checks prior to making changes
     # @return [string] Error message, or nil if success
     def prepare
diff --git a/lib/arduino_ci/arduino_downloader_windows.rb b/lib/arduino_ci/arduino_downloader_windows.rb
index 9b7d1862..ffb952a2 100644
--- a/lib/arduino_ci/arduino_downloader_windows.rb
+++ b/lib/arduino_ci/arduino_downloader_windows.rb
@@ -28,12 +28,6 @@ def package_file
       "arduino-cli_#{@desired_version}_Windows_64bit.zip"
     end
 
-    # The executable Arduino file in an existing installation, or nil
-    # @return [string]
-    def self.existing_executable
-      Host.which("arduino-cli")
-    end
-
     # The technology that will be used to extract the download
     # (for logging purposes)
     # @return [string]
@@ -57,5 +51,11 @@ def self.extracted_file
       "arduino-cli.exe"
     end
 
+    # The executable Arduino file in a forced installation, or nil
+    # @return [Pathname]
+    def self.force_installed_executable
+      Pathname.new(Host.windows_to_pathname(ENV['HOME'])) + self.extracted_file
+    end
+
   end
 end
diff --git a/lib/arduino_ci/host.rb b/lib/arduino_ci/host.rb
index dc8e2911..4cd5e243 100644
--- a/lib/arduino_ci/host.rb
+++ b/lib/arduino_ci/host.rb
@@ -17,13 +17,14 @@ class Host
     # via https://stackoverflow.com/a/5471032/2063546
     #   which('ruby') #=> /usr/bin/ruby
     # @param cmd [String] the command to search for
-    # @return [String] the full path to the command if it exists
+    # @return [Pathname] the full path to the command if it exists
     def self.which(cmd)
       exts = ENV['PATHEXT'] ? ENV['PATHEXT'].split(';') : ['']
-      ENV['PATH'].split(File::PATH_SEPARATOR).each do |path|
+      ENV['PATH'].split(File::PATH_SEPARATOR).each do |string_path|
+        path = OS.windows? ? windows_to_pathname(string_path) : Pathname.new(string_path)
         exts.each do |ext|
-          exe = File.join(path, "#{cmd}#{ext}")
-          return exe if File.executable?(exe) && !File.directory?(exe)
+          exe = path.join("#{cmd}#{ext}")
+          return exe if exe.executable? && !exe.directory?
         end
       end
       nil
diff --git a/spec/arduino_downloader_spec.rb b/spec/arduino_downloader_spec.rb
index 9158b439..6fda6366 100644
--- a/spec/arduino_downloader_spec.rb
+++ b/spec/arduino_downloader_spec.rb
@@ -7,7 +7,6 @@
     it "has correct class properties" do
       ad = ArduinoCI::ArduinoDownloader
 
-      expect{ad.existing_executable}.to raise_error(NotImplementedError)
       expect{ad.extracted_file}.to raise_error(NotImplementedError)
       expect{ad.extracter}.to raise_error(NotImplementedError)
       expect{ad.extract("foo")}.to raise_error(NotImplementedError)
diff --git a/spec/host_spec.rb b/spec/host_spec.rb
index ac40f4e0..f9b94f4b 100644
--- a/spec/host_spec.rb
+++ b/spec/host_spec.rb
@@ -54,7 +54,7 @@ def with_tmpdir(path)
     it "can find things with which" do
       ruby_path = ArduinoCI::Host.which("ruby")
       expect(ruby_path).not_to be nil
-      expect(ruby_path.include? "ruby").to be true
+      expect(ruby_path.to_s.include? "ruby").to be true
     end
   end