---
id: mac-storage-basics.what-is-trim-and-does-my-mac-use-it
url: https://storagestudio.us/faq/mac-storage-basics/what-is-trim-and-does-my-mac-use-it
category: "Mac storage basics"
subcategory: "Disks, APFS and formats"
question: "What is TRIM, and does my Mac use it?"
alt_questions:
  - "trim on mac ssd"
  - "enable trim mac external ssd"
  - "trimforce mac"
  - "does macos support trim"
  - "ssd trim external drive mac"
short_answer: "TRIM tells an SSD which blocks are free so it keeps its speed. Apple's internal SSDs use it automatically; third-party and USB-connected SSDs may not."
tags: ["trim", "ssd", "performance"]
related: ["https://storagestudio.us/faq/mac-storage-basics/what-is-apfs"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# What is TRIM, and does my Mac use it?

**TRIM** lets the operating system tell an SSD which blocks are no longer in use, helping it keep its speed and wear even. Apple's internal SSDs use it automatically.

For third-party SSDs, macOS may not enable TRIM by default; the `trimforce` command can turn it on, but Apple warns it's at your own risk. Many external SSDs connected over USB don't receive TRIM at all and manage themselves. Check a drive's TRIM status in **System Information → NVMExpress or SATA**.