I ran into an issue where I was not able to use the Localization update module in Drupal on an Acquia hosted site. This is because the default location where the module stores translation files, sites/all/translations could not be created due to this directory being write protected. I suppse write protecting any directory location that could contain executable code is a good practice.
A good reason to remove inactive modules: drupal_system_listing(). In some recent on a Drupal 7 site, I kept noticing errors when running database updates via drush, which looked something like this: