What is mlocate can be found here.
By default it is scheduled to execute daily – that might not meet your expectations what you computer should do when you power it on.
Here is how to reschedule it to execute weekly:
### In the terminal sudo chmod -x /etc/cron.daily/mlocate sudo cp /etc/cron.daily/mlocate /etc/cron.weekly/mlocate sudo chmod +x /etc/cron.weekly/mlocate
This has been checked with Ubuntu 18.04 LTS.