[Plugin: WP BUSINESS DIRECTORY MANAGER] Theme loses its header

snails07, the templates used by the plugin are not the same used by your theme. Neither the single page nor the category page template use a sidebar. If you want to make either or both use a sidebar you’ll have to edit the wpbusdirman_category.php for the category page view and wpbusdirman_single.php for the sinlge page view. You’ll find them in the posttemplates folder.

For the disappearing header, what’s the name of the theme? I’d like to take a look at it.

It is the Vodpod theme from Press75

https://www.iloveyouwp.com/press75-vodpod-free-portfolio-wordpress-theme.html

Does this answer my question https://www.ads-software.com/support/topic/394991?replies=1 too?
I tried to use the plugin on a page with a sidebar when all posts on my blog index dissappeared when activating the plugin (only after adding categories)

@snails, if you’re still wrangling with this problem, does your theme use the usual get_header(); call to display the theme header?