How to automatically clean an overcrowded folder on Mac

What this does

Rather than cleaning up on a fixed schedule regardless of how full a folder actually is, this rule waits until the folder is genuinely overcrowded, more than 300 items, and only then starts trashing anything that’s been sitting untouched for 14 days. That combination matters: a file that just arrived five minutes ago is never at risk just because the folder happens to be full.

What you’ll build

A rule that only acts once a folder holds more than 300 items, then trashes items older than 14 days within it.

Open the rule editor

This walkthrough happens inside FilesAutomator itself, so install it from the Mac App Store first if you have not already, then open it. In its toolbar, choose Add, then New Automation Rule.

Name the rule and choose a folder

Name it something like “Trim my overcrowded folder” and use Add Folder to choose the folder you want kept under control.

Build the condition

Leave the top group set to “All of the following are true”.

Add a condition: Folder’s file count is greater than 300.

Add a second condition: Date added is more than 14 days ago.

FilesAutomator

Add the action steps

Step 1: Move to Trash

Choose Add Step, then Move to Trash. This step has no extra fields to fill in.

FilesAutomator

Turn it on

Select Create Automation Rule, then switch the rule on. The folder now trims itself back only when it actually needs it.

A faster way

The template gallery inside FilesAutomator already has this rule ready to install, named Trim an overcrowded folder.