diff --git a/rubygems_plugin.rb b/rubygems_plugin.rb
index 43369da..a7ca45d 100644
--- a/rubygems_plugin.rb
+++ b/rubygems_plugin.rb
@@ -4,5 +4,8 @@
   end
 end
 
-Gem.post_install(&hook)
-Gem.post_uninstall(&hook)
+shims_path = File.join(ENV['RBENV_ROOT'], "shims")
+if File.writable?(shims_path)
+  Gem.post_install(&hook)
+  Gem.post_uninstall(&hook)
+end