Org-Mode not exporting all child subheading

Question

While exporting following sample org file content to html, final output skips headings from 3rd depth in table of content.

After reading org documentation, and forum questions, I tried following, but still no luck in exporting all sub headings.

1. Changed org-imenu-depth to 4
2. Changed imenu-auto-rescan to a non-nil value
3. Chanaged imenu auto rescan maxout to 600000 as file size is 400 KB.

Sample:

* Head 1 shown
* Head 2 shown
** Head 2.1 shown
*** Head 2.3 not shown
* Head 3

Emacs version: GNU Emacs 26.1 (build 1, x86_64-w64-mingw32) of 2018-05-30

Org mode 9.1.9

Answer 1

org-export-headline-levels is the option determining up to which level headlines are included in the table of contents of the exported document.

The standard value of org-export-headline-levels in Orgmode 9.1.9 is 3.

I tested your example org file with this standard setting and Head 2.3 was also included in the table of contents. That indicates that you have customized org-export-headline-levels to a lower value in your configuration.

You can easily increase the default value for org-export-headline-levels with M-x customize-option RET org-export-headline-levels RET.

All org documents will work with this default value if you do not set the value of org-export-headline-levels explicitly in the document.

You can set the value explicitly locally for one org document with a line like the following:

#+OPTIONS: H:5

Adapt the value 5 to your likings.

Equivalently you can set the option as file local variable:

1. Either use the following first line for the org file:
   # -*- org-export-headline-levels: 5 -*-

2. or append the following section to your org file. It does not hurt since it is excluded from export.

   * Local Variables :noexport:
   Local Variables:
   org-export-headline-levels: 5
   End: