Apache Friends Support Forum

God day for everybody.
I have just got a terrible situation with brand fresh XAMPP 5.6.12-0 instalation in Ubuntu 15.04
Worst thing is the mesagge:
sudo /opt/lampp/lampp start
[sudo] password for ricardo:
Starting XAMPP for Linux 5.6.12-0...
XAMPP: Starting Apache...fail.
XAMPP: Starting diagnose...
XAMPP: Sorry, I've no idea what's going wrong.
XAMPP: Please contact our forum http://www.apachefriends.org/f/
Last 10 lines of "/opt/lampp/logs/error_log":
XAMPP: Starting MySQL...ok.
XAMPP: Starting ProFTPD...ok.
ricardo@laptop-dell-n4050:~$ mysql -u root -p
Enter password:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/opt/lampp/var/mysql/mysql.sock' (2)

I think, you already have installed Apache (and maybe also MySQL etc.) from your Ubuntu Software Setup. This collides with Xampp. you cannot use both of them.