Problem:


It may happen that the administration page /wp-admin/ is not displayed after updates of the Wordpress Content Management System.


Cause:


This is mostly due to outdated plugins or other incompatibilities. Outdated plugins are often not compatible with newer Wordpress versions.


Solution:


a: Disable all plugins


b: Clear Browser Cache


c: If everything works again, you can activate the plugins individually.


Optional solution:


Add the following code to the file wp-config.php above:


define('CONCATENATE_SCRIPTS', false);


This forces Wordpress to load all scripts individually. If one of the scripts cannot be loaded, the others will still be loaded and executed. 


However, this does not eliminate the cause, but you can work again first.