I have a MacBook Pro 13-inch Mid 2012 and I installed an SSD in it. I'd like to upgrade my computer, but I'm not sure if I need to disable the trim before the update and reenable it after. I've heard that it could cause problems, but don't know why.

I have macOS Sierra 10.12.6 and I've enabled the trim since I switched to this operating system.

  • I upgraded with TRIM enable (from terminal) and it worked. Thanks! Commented Dec 28, 2017 at 1:17

1 Answer 1


TRIM is a subset of the ATA commands specific to SSDs.

Can you operate without it? Sure, but it will treat your SSD as if it were a spinning HDD - impacting performance and lifespan.

From Wikipedia:

The TRIM command enables an operating system to notify the SSD of pages which no longer contain valid data. For a file deletion operation, the operating system will mark the files sectors as free for new data, then send a TRIM command to the SSD. After trimming, the SSD will not preserve any contents of the block when writing new data to a page of flash memory, resulting in less write amplification (fewer writes), higher write throughput (no need for a read-erase-modify sequence), thus increasing drive life.

If your MacBook Pro came with an SSD, it's enabled by default. If not, you must enable TRIM when you upgrade to an SSD.

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