Flash storage higher than calculated storage.

jxyzz_ wrote:

Hello, thank you for your response, I have just checked, and I don't think there are any extra volumes/partitions here.

https://discussions.apple.com/content/attachment/4397bdb9-f024-404e-975c-82f8899ab1e5

Am I doing something wrong here?🥲

The hard truth is, the 128 GB Internal Drive is too small the run both macOS Monterey and a Bootcamp Partition for MS Windows 10.

macOS in and of itself will generally command about 19 GB of Space and then the Third Party Applications installed in macOS plus the User Account

Through in a Bootcamp Partition which is created by Bootcamp, you will have very little space to do what you want to do

Install Windows 10 on your Mac with Boot Camp Assistant

1. These Mac models were offered with 128GB hard drives as an option. Apple recommends 256GB or larger hard drives so that you can create a Boot Camp partition of at least 128GB.

We need a better look at the drive layout here. Use the following command in the Terminal app so we can see the complete drive layout:

diskutil  list  internal

FYI, when you acquire a used computer you should always perform a clean install of the OS by first erasing the whole physical drive followed by reinstalling the OS. It is best to first create a bootable macOS USB installer now while you still can since some people have issues using Internet Recovery Mode (Command + Option + R) to reinstall macOS.

Here is what your aunt should have done prior to giving you the computer:

What to do before you sell, give away, trade in, or recycle your Mac - Apple Support

Like the others have already mentioned, a 120GB SSD is way too small to dual boot with Windows. You need to alway keep at least 20GB+ of Free storage space at all times for the normal operation of macOS. Ignore the "Available" designation since it is very misleading......you need to reference the Free storage space which can be seen in Disk Utility or in the System Profiler. It is unfortunate that Apple chose to use the "Available" storage designation & term everywhere within macOS.....the Free storage space value is the critical one.

macOS Storage & terminology explained -- hwtech - Apple Community

If you've been using Time Machine regularly see if this helps:

The files that you have control over are located in the Documents, Downloads, Pictures, Music and Movies folders.  You can use this free app, GrandPerspective, to find the largest files on your drive so you can determine if they can be deleted or moved to an external HD for storage.

Note: you can empty the Downloads folder after the apps and/or updates that were downloaded have been installed or applied.  Some users have found a couple of Gigabytes of files in their Downloads folder which are no longer needed. 

If you find you may need an external drive to hold some files give a look at this one from OWC (MacSales.com). It's very easy to carry with a laptop:

I recommend drives from OWC (MacSales.com) as they have proven reliability, excellent customer support and warranties.  Consider one of these depending on your budget and needs: 1TB OWC Envoy Pro mini 

Check if there is some dummy partition taking space. Sometimes you might need to erase the disk to do that, depending where that partition is.