System storage on OSMojave over 72gb, how do I reduce this?

Have been a faithful Apple Eco-System user since the Powerbook PPC Motorola CPU with Tiger OS X 10.4 and for a ever long time, Apple has sold laptops with the tiny 128 GB SSD drives.

Agree, should not have been offered especially as the newer versions of macOS are more robust requiring bigger SSD Internal Drives.

But it is what it is.

What is “Other” storage on a Mac, and how can I clean it out?

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The final word from Apple on Managing the " Other " Category

• Other: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources. Also included are temporary files, fonts, app support files, and plug-ins. You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.

It is clear to me that you have a lot of data and you have small hard drive. The solution is going to be for you to install an external drive, then transfer data to it such as photos and music, and then delete them from your hard drive to clear the needed space. For your information, I offer the following information, which is important to know.

The Other Category should not be altered, modified, move or deleted since it is part of the Mac’s operating system. Doing so would corrupt the OS and render the OS inoperative requiring a Wipe and Re-Installation.

The Other category is a potpourri of files which include:

• System temporary files

• macOS system folders

• Archives and disk images (.zip, .iso, etc. - often found in the Downloads folder)

• Personal user data

• Files from the user’s library (Application Support, iCloud files, screensavers, etc.)

• Cache files

• Fonts, plugins, extensions

• Other files that are not recognized by a Spotlight search

• Media files that cannot be classified by Spotlight as a media file because they are located inside of a package

They can be located anywhere on your hard drive. The files that you have control over are located in the Documents, Downloads, Pictures, Music and Movies folders.

Also, if your OS becomes too full your computer will stop functioning.

Indeed: there is something wrong.

Do not use About-this-Mac to get some info: but use the app: Applications->Utilities->SystemInformation.

First check the list "Software" "Applications" to see if there is running a spook or something.

If it does not go away after a restart:

download Etrecheck and run it to have an analysis and info about what is wrong.

somehow my system storage has ballooned to 680G on TB drive. Removed all local backups and using a 4TB external, still my Mojave 21" is slow. been through the disk utility steps from restart drive is good. Looks unfixable but to go back in time. Apple is not as nice as 5, 10 or 27 years ago when i bought my first 7100AV...