How to fix “unable to lock database” error in Apricity Os

This guide will show you how to fix  “unable to lock database” error in Apricity Os, For the first time encounter this issue really don't know what to do because just finish installed Apricity Os and not even touch, it showed an error, and won’t let me to update

Command to update :

pacman -Syu

Then error showed :

:: Synchronizing package databases...
error: failed to update core (unable to lock database)
error: failed to update extra (unable to lock database)
error: failed to update community (unable to lock database)
error: failed to update multilib (unable to lock database)
error: failed to synchronize any databases
error: failed to init transaction (unable to lock database)
error: could not lock database: File exists
 if you're sure a package manager is not already
 running, you can remove /var/lib/pacman/db.lck

It said, if you're sure a pakage manager is not already running, you can remove /var/lib/pacman/db.lock

So i tried to remove it:

rm /var/lib/pacman/db.lock

Awesome, it worked..Now can update and install any application

pacman -Syu