Not sure I have encountered this one. The parent class indication tells me this is a Blueprint-created class (default from new project template?) so it’s not like you may have done something weird in code (can’t remember if there are any metatags making event graphs uneditable). My best guess would be that perhaps the Blueprint has been corrupted now. If you have an earlier version from source control try and revert to that and maybe this will help you restore and figure out when things started going bad. Look into your Saved folder as well in case there is an Autosave of it there.