Macbook Pro El Capitan shuts down only in safe mode

Hi there,

Since I upgraded from Mountain Lion to El Capitan two years ago, my MacBook Pro (2012) won't shut down any more (and won't restart neither) but in Safe Mode. So, I cope by shutting it down manually by pressing the Switch on / off button. For the minor security updates – where restart is needed –, I used to boot in Safe mode, where it would allow me to shut down and/or restart properly.

Now, I'd like to update to High Sierra, but several consecutive shuts down are needed, so my ‘trick’ isn't working any more.

I tried to delete all apps that automatically open on startup in SystemPreference/Users and groups/[Username]/Opening – like I read the advice somewhere on the net – but I won't change anything - my computer still doesn't want to shut down. Any idea how to fix this ?

Thousands of thanks !

Sebastian