If you are attempting to save an XDP file in LiveCycle Designer ES2, created with an earlier version of Designer (i.e. 7, 7.1 or ES), then it can occur that the Save process never completes, and you must kill the Designer process manually in Task Manager. If you analyse the files on your local disk, you will notice some tmp files with large file sizes.
This issue is related to the Data Binding option Allow binding to data not defined by the default data connection. For some forms that contain data connections, Designer ES2 can get stuck in an endless loop while saving the XDP to an intermediary tmp file. You will see the tmp file will contain a huge number of repeated entries related to the DataDescription similar to the following:
<DATACONNECTION xmlns:dd=”http://ns.adobe.com/data-description/” dd:additions=”$template(DATACONNECTION)”/>
Read the complete post at Adobe LiveCycle Blog.