How do I defragment a MacBook Pro?

You not defrag an SSD. 

The answer is short and simple — do not defrag a solid state drive.

At best it won't do anything, at worst it does nothing for your performance and you will use up write cycles. If you have done it a few times, it isn't going to cause you much trouble or harm your SSD. You just don’t want this to be a scheduled, weekly type thing that takes away from the finite number of SSD rewrites. There are other ways to clean up your computer. There just isn’t a reason to defrag an SSD.

BTW, there are no instructions on the Apple Support for doing this.

You don't NEED a tool to do this.

MacOS defragments as it runs. When fragmented files are opened, they are re-written. the allocation algorithm is "First Fit", so the new area will be contiguous if possible.

Also, de-fragementation is a solution to too many long disk seeks on Rotating Magnetic drives. Your MacBook Pro from 2015 uses a Solid State Drive (SSD) that has minuscule seek time that is the same for every block. So de-fragmentation does not improve performance.

Are you having symptoms of slowness? what is your complaint?

anesthesia202 wrote:

how do i defragment a mac pro book purchased 12/2015? does it have a tool to do such

The best way on your SSD is make a copy like for ex Carbon Copy Cloner

then erase/reformat/initilze your internal parent Drive as new— and simply clone back to the internal drive.

You can boot off your new clone to acess the DiskUtiliy>View>Show all Devices for this action.

How to erase your Intel-based Mac - https://support.apple.com/en-us/HT208496

( in the end verify TRIM is re-enabled to do the garbage collection/maintenance on the internal SSD )

anesthesia202 wrote:

how do i defragment a mac pro book purchased 12/2015? does it have a tool to do such

Interestingly enough...

I will add— that I was shocked by the large amount of free GB returned to my internal SSD drive when I followed the procedure as described above...

Simple enough to compare your results and report back you findings, you certainly will do no harm.

I would not use the word defrag either. ...

note: choose the erase that is the simplest/ fastest erase, not the multiple r/w erase as government security erase.