Pacman Unable to Lock Database

On a recent pacman upgrade, I encountered the error:

:: 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 synchronize all databases

the solution everytime is to remove the db.lck from the /var/lib/ directory and restart pacman.

rm /var/lib/db.lck
pacman -Syyu