If you're making major changes to your TOC that you may not want to be permanent, you can periodically save backup versions of your TOC, just in case you decide to go back to a previous version later in the authoring process.
It is very easy to export a backup version of your TOC by using the "Export TOC" feature, accessible by clicking the arrow button at the top right of the TOC column and selecting "Export TOC" from the options menu. From the Save As dialog window that appears, choose a location where you wish to save your backup TOC file. By default, HelpLogic provides a date-based filename for your convenience, such as "HLTOC_2009-10-15.xml", but you may name the file whatever you want. Since the backup file is in XML format, do NOT change or remove the .xml file extension.
To replace your project's TOC with a HelpLogic XML backup TOC file you saved, click the arrow button at the top right of the TOC column and choose "Replace TOC" from the options menu. From the Open dialog window that appears, simply select the XML backup file that you wish to use. After the project's TOC is successfully replaced with your backup TOC, save your project to lock in your new TOC data. For more information on restoring your TOC with a backup file, please see the Replacing Your TOC page.