diff --git a/TODO.md b/TODO.md
index 9a80fb82d91..028a657a49c 100644
--- a/TODO.md
+++ b/TODO.md
@@ -6,7 +6,6 @@
   - bundle irb / bundle ruby / bundle [whatever] -> bundle exec
   - Make bundle (install) work when sudo might be needed
   - Generate a bundle stub into the application
-  - Handle materialization errors
   - Handle the following case (no remote fetching):
     1) Depend on nokogiri, nokogiri is installed locally (ruby platform)
     2) Run bundle package. nokogiri-1.4.2.gem is cached
diff --git a/lib/bundler/spec_set.rb b/lib/bundler/spec_set.rb
index 6eb727e4496..32c9bf9e2b5 100644
--- a/lib/bundler/spec_set.rb
+++ b/lib/bundler/spec_set.rb
@@ -72,7 +72,7 @@ def materialize(deps, missing_specs = nil)
         if missing_specs
           missing_specs << s unless spec
         else
-          raise "Could not materialize #{s.full_name}" unless spec
+          raise GemNotFound, "Could not find #{s.full_name} in any of the sources" unless spec
         end
         spec if spec
       end
diff --git a/spec/runtime/platform_spec.rb b/spec/runtime/platform_spec.rb
new file mode 100644
index 00000000000..5137ea6060d
--- /dev/null
+++ b/spec/runtime/platform_spec.rb
@@ -0,0 +1,34 @@
+require "spec_helper"
+
+describe "Bundler.setup with multi platform stuff" do
+  it "raises a friendly error when gems are missing locally" do
+    gemfile <<-G
+      source "file://#{gem_repo1}"
+      gem "rack"
+    G
+
+    lockfile <<-G
+      GEM
+        remote: file:#{gem_repo1}/
+        specs:
+          rack (1.0)
+
+      PLATFORMS
+        #{local_tag}
+
+      DEPENDENCIES
+        rack
+    G
+
+    ruby <<-R
+      begin
+        require 'bundler'
+        Bundler.setup
+      rescue Bundler::GemNotFound => e
+        puts "WIN"
+      end
+    R
+
+    out.should == "WIN"
+  end
+end
\ No newline at end of file