WYSIWYG editor stopped working after update

Hi,

after updating from 13.1 to 13.5 the WYSIWYG editor stopped working. When editing a page only the spinner shows up and keeps spinning infinitely, the editor is never loaded. Switching to text mode edit works.

I have tried clearing the browser cache but this does not help. Also checking the browser and webserver logs does not show any issues. Any suggestions on how to debug this any further would be appreciated.

I have installed Visual Realtime Collaborative Editor 1.37 for 13.1, which did work. After upgrading to 13.5 I suspect this might cause some issue, but uninstalling is not possible, clicking the uninstall button in the list of installed extensions also does not do anything.

Is there a way to reset all installed extensions and settings to default mode without losing the content and users?