My MBP is a 2016 Model Identifier: MacBookPro13,3; it has a 500 GB drive. I've upgraded the OS from Mojave in the beginning, to Monterey just recently. Everything seems to be working as it should, but my SSD is near the limit (see screenshot below).

I don't understand how I have gotten to nearly 350 GB. Someone suggested that the upgrades, and "general usage" may lead to a lot of cruft in the file system. At any rate, I removed about 80 GB of data earlier today after copying it to another drive. The totals shown below are after removing the files I wanted to keep.

I found a procedure from the macos User Guide named "Erase and reinstall macOS", but at the bottom of that page it has another option for Erase your Mac.

I have several apps I don't need, and Desktop and Documents are "in the cloud". I'd be happy to still have things like my iCloud account, but will gladly forego that if it frees up 30 GB or more.

Which of these two options will result in the most free space on my SSD? Are there other pros & cons to be considered?


  • 2
    Welcome! Before taking such drastic steps like erasing and reinstalling macOS, take a look at this excellent question and its answers first. Wiping a drive and reinstalling is usually a last resort type of action.
    – Allan
    Dec 29, 2022 at 7:04

1 Answer 1


Lots to unpack here. First, if you do want to 'wipe clean' your Mac, then you should use the Erase Assistant, as outlined in the Apple Support document. (In later OSes, you can Erase all Content from the OS Settings.)

There's nothing wrong with the disk format itself, so leave that alone. (Similarly, there's no point in erasing the OS itself, as it is immutable.)

The best way to deal with a full disk is to use an app like OmniDiskSweeper (there are others, but this one is free), which will show you a listing of each folder on your disk, sorted by size. You can then drill down and find which files are using the most space.

The biggest use of space is likely to be: user stuff. You might have old installers of apps still left in Downloads; otherwise, it will be documents, videos, music, photos, etc.

Some apps can be very large (MS Office apps are over 1Gb each). Things like Logic and MainStage have large libraries of support files in /Library/Application Support (NB: this is the root level Library, not the User library.)

Otherwise, the dangers of CRUFT!!! are largely overstated. Sure, if you've deleted some apps, then there might be some configuration files left in the user Library (e.g. ~/Library/Application Support).

I would advise against using apps like CleanMyMac or other 'cleaning' tools. At best, they miss stuff; at worst, they delete things that they shouldn't. Emptying caches, for example, is a largely fruitless exercise, as they will just refill again.

TBH, 150GB free on a 500GB disk is more than sufficient.

  • Thanks for the response. But I gotta wonder is the OS really 300GB? Dec 31, 2022 at 13:15
  • @TurnerMoore Where did you get that figure from?
    – benwiggy
    Dec 31, 2022 at 15:46
  • As shown by the screenshot in my post, there's almost 350GB being used. Without going into too much detail, I can only account for ~35GB. I have no idea what is occupying the rest. Jan 1, 2023 at 22:38
  • @TurnerMoore Well, then you don't know it's "OS". Have you used OmniDiskSweeper to see what's eating your space?
    – benwiggy
    Jan 2, 2023 at 12:51

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .