Call to a member function getGroups() on null

[Asmaalamine]

Hi everyone, I am working on my Prestashop website , i needed to make the menu full widh display , I was looking for a solution , so I looked over Design/ Position/ Megamenu, I started changing the transplant to see what it will looks like, I tried 3 or 4 times, suddenly this error appeared 

Call to a member function getGroups() on null

[Symfony\Component\Debug\Exception\FatalThrowableError 0]

Any help please ! 

[Massimo333]

It's probably a plugin causing that error, do this: activate prestashop debug mode (menu "Advanced parameters > Performance > Enable debugging") and see which plugin is causing the error. Try deactivating/uninstalling the plugin to see if the error is resolved.