Again, hard to tell from here, since this is obviously a custom website. I can give you all kinds of ideas on how to approach this, but...

Please ask your client why they need empty pages to be published on the website at all? Because if there is no reason then this is serious nonsense!

You haven't responded to this question, and I think you need an answer before hacking on any further... :)

Btw: there should be another option I hadn't even mentioned (stupid me): you can also remove pages from menus and searches within the cms. That could be a solution for now

Find the page in the cms, go to settings and deselect 'show in menus' - I don't know the label name in German...

i think the problem is that this are not real pages, you see it in the screenshot.
empty pages are ofcourse not needed, but some "company sites" has content under "Geschichte" and some not.
i dont know where they load the content from it ...
problem is that there is one page thats called "Geschichte" and the content changes within the scope-id
i tried to upgrade to a newer version dont work too...
seems not good to me :(

Ok, I'm beginning to get this... The items on the right are definitely pages, but they get their content from the Unternehemen, based on the company selected on the right. Not to confuse the Unternehmen page with the Unternehmen DataObject that can be edited through the menu item in the top bar. That object class may be called Unternehmen or Company or...

Unfortunately there are many ways this can be accomplished. Other pages seem to be empty as well and their content is based on differen Unternehmen data, meaning different data fields...

So I really can't tell you how to go about solving this, without having a look at the code. It'll probably not be very hard to find, but without code... I'm sorry, you'll need someone who understands SilverStripe...

first... thank you for your fast help. really. thank you ! i really appreciate this ! Thank you !
i can write php code, thats np for me. but i'm not in silver stripe... its completely new for me.
i see many classes and functions in the code, i investigate... but can't find the place where they are called.
can you recommend anybody who can help me ?

Hmm that's hard to say - there are lots of SilverStripe programmers and anyone who reads this post and thinks they can be of help, can respond...

Also there is this: https://www.silverstripe.org/community/developer-and-partner-directory/

If you can't find anyone, send me a personal message, although - warning :) - I don't have much time available at this point...