I keep getting alerts saying that "your start-up disk is almost full".
I have an early 2015 13 inch MacBook Pro running macOS 10.11.6 with a 128MB SSD that has 63GB free according to About this Mac > Storage. I have created two other standard user accounts for my wife and son. I typically see this issue after coming home from work after they have been using it. If the alert appears, About this Mac > Storage will indeed indicate that all storage has been used, the bulk being of type: Other. When this happens, any open apps are sluggish, frequently showing the spinning wheel cursor and preventing saving.
Restarting the system solves the issue. If I had to guess, it seems like some program is hogging all disk space for swap space. The only app with which I am unfamiliar and didn't install myself is Discord which my wife installed for my son.
Any thoughts on what could be causing this phantom disk usage?