My system settings application is not opening I tried many times but still I can’t open it
Try running it from a terminal. Type
systemsettings
in Konsole and tell us what message it gives you.
Actually, to be sure, it’s best to do this:
pkill systemsettings
systemsettings
The last time I had it fail to launch, there were no messages - but after I tried killing it first - it started up fine.
Good point. Yes.
Thank you 
it worked