What is .TPD file extension?
File created by TreePad 7 or later, a personal information manager; stores information that is structured as a hierarchy of "nodes," each of which stores document content such as text, images, hyperlinks, structured data, and other personal content.
NOTE: Prior to TreePad 7, the software used the .HJT file extension for databases.
You can see a list of software programs here on easyfileopener.org that can open this file type so that you don’t need to search for it on the web. You can then open your file with this extension using a software listed below.