Did you know that every time you download something to your Mac, a record of this downloaded file is added to a log and retained on your system? It could be anything from an image from Google, a PDF document from your boss or a pirate movie. If you download it to your Mac laptop hard drive, it will be saved to the log.
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Η Apple does not advertise that something is happening and we have no idea what exactly is happening. Maybe for troubleshooting reasons, who knows? But in terms of privacy, this is quite annoying, especially if someone is watching your computer and knows where to locate the log. If you have a habit of downloading a lot, having a log of all the things you have downloaded is of course not safe.
To learn how to delete the hidden download log on your Mac, read the instructions below.
First, locate the log file
It is very easy to find the log. Open a Terminal window and type:
sqlite3 ~ / Library / Preferences / com.apple.LaunchServices.QuarantineEventsV * 'select LSQuarantineDataURLString from LSQuarantineEvent'
This will then create a complete list of your downloads from the last time you deleted it. If this is the first time you see the list, the list may start from the first day you bought your Mac!
Now delete the log
Deleting it is not difficult. Just enter in Terminal:
sqlite3 ~ / Library / Preferences / com.apple.LaunchServices.QuarantineEventsV * 'delete from LSQuarantineEvent'
The download list will be deleted. If you run the first command again, you will receive an empty list.
Ideally you should do this once a week or once a month, depending on the amount of your downloads and who else has access to your Mac laptop. To facilitate the task, you can run an Automator script with the command, so that it can be done with a single click of the mouse or trackpad.
Source of information: xda-developers.com