HI,
I’d suggest you to check the path of the Themes folder
1) Open D2h
2) Click on Files>Doctohelp options>Files
Check for the default location of Themes folder there, and set it as
//Documents/My Doc-To-Help Projects/Doc-To-Help/Themes
Now, close d2h and open it again
1) Click on THEME>Add new Theme> in the dropdown check if the default BASIC theme is present
2) Make the basic theme as source and create a new theme
The location of your new theme would be
//Documents/My Doc-To-Help Projects/Doc-To-Help/Themes/Eclipse/themes
Let me know your observations.