diff --git a/lib/jekyll/commands/build.rb b/lib/jekyll/commands/build.rb
index 3e43f955..3cea607c 100644
--- a/lib/jekyll/commands/build.rb
+++ b/lib/jekyll/commands/build.rb
@@ -71,23 +71,27 @@ module Jekyll
         #
         # Returns nothing.
         def watch(site, options)
-          if Utils::Platforms.windows?
-            Jekyll.logger.warn "", "--watch arg is unsupported on Windows. "
-            Jekyll.logger.warn "", "If you are on Windows Bash, please see: " \
-              "https://github.com/Microsoft/BashOnWindows/issues/216"
+          # Warn Windows users that they might need to upgrade.
+          if Utils::Platforms.bash_on_windows?
+            Jekyll.logger.warn "",
+              "Auto-regeneration may not work on some Windows versions."
+            Jekyll.logger.warn "",
+              "Please see: https://github.com/Microsoft/BashOnWindows/issues/216"
+            Jekyll.logger.warn "",
+              "If it does not work, please upgrade Bash on Windows or "\
+                "run Jekyll with --no-watch."
+          end
 
+          External.require_with_graceful_fail "jekyll-watch"
+          watch_method = Jekyll::Watcher.method(:watch)
+          if watch_method.parameters.size == 1
+            watch_method.call(
+              options
+            )
           else
-            External.require_with_graceful_fail "jekyll-watch"
-            watch_method = Jekyll::Watcher.method(:watch)
-            if watch_method.parameters.size == 1
-              watch_method.call(
-                options
-              )
-            else
-              watch_method.call(
-                options, site
-              )
-            end
+            watch_method.call(
+              options, site
+            )
           end
         end
       end # end of class << self
diff --git a/lib/jekyll/utils/platforms.rb b/lib/jekyll/utils/platforms.rb
index a16c239b..f66ef795 100644
--- a/lib/jekyll/utils/platforms.rb
+++ b/lib/jekyll/utils/platforms.rb
@@ -19,16 +19,29 @@ module Jekyll
       # /proc/version returns nothing to us.
       # --
 
-      def really_windows?
+      def vanilla_windows?
         RbConfig::CONFIG["host_os"] =~ %r!mswin|mingw|cygwin!i && \
           !proc_version
       end
 
+      # --
+      # XXX: Remove in 4.0
+      # --
+
+      alias_method :really_windows?, \
+        :vanilla_windows?
+
+      #
+
+      def bash_on_windows?
+        RbConfig::CONFIG["host_os"] =~ %r!linux! && \
+          proc_version =~ %r!microsoft!i
+      end
+
       #
 
       def windows?
-        RbConfig::CONFIG["host_os"] =~ %r!mswin|mingw|cygwin!i || \
-          proc_version =~ %r!microsoft!i
+        vanilla_windows? || bash_on_windows?
       end
 
       #