diff --git a/plugins/providers/virtualbox/driver/base.rb b/plugins/providers/virtualbox/driver/base.rb
index 22dcfe96d..a3892eb06 100644
--- a/plugins/providers/virtualbox/driver/base.rb
+++ b/plugins/providers/virtualbox/driver/base.rb
@@ -289,6 +289,9 @@ module VagrantPlugins
               if @interrupted
                 @logger.info("Exit code != 0, but interrupted. Ignoring.")
               elsif r.exit_code == 126
+                # This exit code happens if VBoxManage is on the PATH,
+                # but another executable it tries to execute is missing.
+                # This is usually indicative of a corrupted VirtualBox install.
                 raise Vagrant::Errors::VBoxManageNotFoundError
               else
                 raise Vagrant::Errors::VBoxManageError, :command => command.inspect