On Wed, 18 Jan 2017, Young-whan wrote:

> I've installed the emacs-app via port, and there was no problem with Latex
> Preview Fragment in a buffer at all.
>
> Now, using the M-x package-list-packages, I've installed the latest org
> 9.0.3, then the latex preview is not working at all.
>
> It comes with following error:
>
> org-create-formula--latex-header: Symbol’s function definition is void:
> org-export-get-backendError during redisplay: (eval (mode-line-mode-name))
> signaled (void-function mode-line-mode-name)

That is because `org-export-get-backend' is not loaded (nor autoloaded).

You can type C-c C-e q to force loading of the org-export-* functions. Or 
put (require 'ox) in your init file.

I don't see why `org-export-get-backend' is lacking an autoload directive.

Bug??

Chuck