I suggest you rebuild the menu and see if there are any items in the trash

@csthomas how to rebuild the default admin menu? Have some issues too (but not with core)

@coolcat-creations Check value of menutype field in #__menu table if this problem start occuring after update to Joomla! 3.7.x.

There is only one button in the menu list "Rebuild" which rebuild whole #__menu table.
If you can not find some menu items then first check trashed items.
There may disappear some menu item from front end and go to backend. If yes then check menutype column in database (ex. by phpmyadmin). One menutype (I do not remeber now) is only reserved for backend.

@csthomas @wojsmol No after the Update just some Menuitems (from not core components) have missing language strings, are in uppercase and some new appeared that have nothing to do with appearing there. I speak about the core admin backend menu, nothing build by myself.

@coolcat-creations

and some new appeared that have nothing to do with appearing there

Should these menu items be displayed in the frontend menu and appear in the backend in the Components menu?

@wojsmol

The Screenshow shows "LANGUAGEFILESJS_MENU"
I don't think it belongs to the frontend... And no idea where it comes from.

Looks to me that screenshot does display apparently a language constant, and you can't translate a constant to English, just its value. And it is for sure NOT a joomla core lang constant.
Best way too know is to set debug lang to on and look at bottom of page which lang file is NOT loaded to figure which component is concerned

you can also execute this query in phpmyadmin

SELECT `menutype`,`link`,`component_id`,`client_id` FROM `#__menu` WHERE `title` = 'language_constant'

replace #__ with table prefix

Thanks that was indeed a component that appeared in the menu after update, but did not appear before the update - i uninstalled it and now it´s fixed - some more language strings in the menu are untranslated after the update, will try to reinstall the components to fix that issue.

Set to "closed" on behalf of @franz-wohlkoenig by The JTracker Application at issues.joomla.org/joomla-cms/17934

As there are similar Threads this is closed but can always reopened.