System storage does not match

[Rogan-J]

Hi there,

I have a 2015 mac running High sierra 10.13.6. I am trying to free up some space on my mac as I have encountered a 'storage full' warning a couple of times so I am trying to prevent this from occurring again. When I look at 'about this mac', it seems that the system takes up a large part of the disk space. However, when I look at the storage using Omnidesk and using the finder it gives me much smaller and different sizes. I am just wondering how I could find out what is taking up that space. When I look using Omnidesk the split between all my folders seems to be reasonable, (I think!), with nothing being too excessively large. Also, the overall HD space in 'about my mac' is not the same as in OmniDesk. Any help on how I could find out what is taking up the system storage, how I could free up some space, as well as any issues you see in the screenshots would be very much appreciated. Thank you!

 

[KeesMacPro]

Hi,
Differences in shown file sizes and/or free space when running a Mac OS from the last ~ 5 years, are normal and nothing to worry about .
There are explanations for this phenomenon relatively easy to find googling it.

Anyway, you didnt mention the exact Mac device you're using, so i'm not sure if a larger SSD can be installed easily (in case of e.g. an iMac it's possible but should be done by a professional/experienced person).
128GB is very little for a system + data disk ....
So , if replacing the drive for a larger one is not an option, I would either store all large personal files (photos,music etc) on an external disk or in iCloud.

Personally I would not start removing system files or install 3rd party software to "clean it up" .
Even if you'd remove a few GB of unnecessary files, within a near future you may run into the same problem, because of newer data added...

As a rule of thumb : it's recommended to keep min ~20% of storage capacity free in order to let the SSD work properly, so effectively your max storage at the moment is ~ 100GB.