SharePoint 2010 Set - Overwrite existing files checkbox - to default to unchecked

Uncheck the Overwrite existing files when uploading a new document

If you would prefer users not to overwrite existing files by default when they upload new documents in SharePoint try adding the javascript below to the bottom of your System master page file just above the PlaceHolderFormDigest control.


<script type="text/javascript">
  document.getElementById("ctl00_PlaceHolderMain_UploadDocumentSection_ctl03_OverwriteSingle").checked = false;
 </script>

Simple but effective - Let me know if this helps you!!