My boss likes the "Lock Document after Signing" option in Acrobat X and plans to use it every time he signs a document. So, is there a way to keep that box checked by default? I did not see it anywhere in preferences, is there a registry key I could set?
There is not a preference for this. It is possible to use seed values for digital signature fields, making it possible to create a custom menu item or toolbar button that adds a digital signature field to a page with the seeds values that would cause the document to be locked when signed. For a bit more information, see: http://livedocs.adobe.com/acrobat_sdk/9.1/Acrobat9_1_HTMLHelp/JS_API_AcroJS.88.757.html