I believe that when I got my MBP, the size was around 16 GB.
One night the size of the 'System' section of my storage increased 40 GB in an hour (though, I am running the High Sierra Beta). I restarted a few times and nothing seemed to happen. I read an answer somewhere to an issue related to this that I could delete the com.apple.coresymbolicationd
folder in /System/Library/Caches/
. The system couldn't read the size of the directory so I figured it was a problem folder, so I deleted it, emptied the garbage, and restarted. Now my System section is 50 GB (used to be 120 GB).
Disk Inventory X gave me different sizes than the System Information window and it didn't find any problematically large files. Daisy Disk, however, did find a glob of ~75 GB that it couldn't scan because of permissions, even when scanning as admin. The com.apple.coresymbolicationd
directory has restrictive permissions, so I assume that was the culprit.
Deleting that directory isn't harmful to the system as far as I know, and it regenerates when the OS needs it again.
You can also look at the built in Disk Utility. That gave me conflicting reports each restart but did inform me on one restart that ~100 GB of data was purgeable.