Installazione e aggiornamento > Installation and Configuration Guide - Update Existing Installation > Planning Before Updating an Installation > Using Best Practices When Updating a Release
  
Using Best Practices When Updating a Release
If the implementation of Windchill at your site involves modifying files supplied by PTC, it is important to understand that the maintenance installation process could overwrite any file that is delivered by PTC (except for the site.xconf file). This includes files that you may have modified.
If you have made site modifications and you are updating to a maintenance release or point release, PTC recommends that you follow the best practices established in the Best Practices for Customizing Files Supplied by PTC.
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Before attempting to access any part of the Windchill system ensure that all installation procedures have been completed.