diff --git a/lib/file_presenter.rb b/lib/file_presenter.rb
index 08c4d43..f0e926d 100644
--- a/lib/file_presenter.rb
+++ b/lib/file_presenter.rb
@@ -51,7 +51,12 @@ class FilePresenter
   end
 
   def short_description
-    _("File (%s)") % content_type.sub(/^application\//, '').sub(/^x-/, '').sub(/^image\//, '')
+    file_type = if content_type.present?
+      content_type.sub(/^application\//, '').sub(/^x-/, '').sub(/^image\//, '')
+    else
+      _('Unknown')
+    end
+    _("File (%s)") % file_type
   end
 
   # Define the css classes to style the page fragment with the file related
diff --git a/test/unit/file_presenter_test.rb b/test/unit/file_presenter_test.rb
index 9b0d9f7..917885f 100644
--- a/test/unit/file_presenter_test.rb
+++ b/test/unit/file_presenter_test.rb
@@ -62,4 +62,16 @@ class FilePresenterTest < ActiveSupport::TestCase
     f = FilePresenter.for(UploadedFile.new)
     assert f.kind_of?(UploadedFile)
   end
+
+  should 'not crash with uploaded_file short description without content_type' do
+    f = FilePresenter.for(UploadedFile.new)
+    assert_nothing_raised do
+      f.short_description
+    end
+  end
+
+  should 'show unknown type when file doesn\'t have a content_type' do
+    f = FilePresenter.for(UploadedFile.new)
+    assert_match /Unknown/, f.short_description
+  end
 end
--
libgit2 0.21.2