It was notorious for its crashes and reporting discrepancies, but now it’s incorporated in System Settings it’s more reliable and helpful. But there’s still the problem of System Data.
DaisyDisk
Why upgrading to Tahoe shouldn’t consume the last free space on your Mac’s SSD, and once it has settled should use little more than currently. How to clear out old snapshots and reduce System Data.
What do you do when you discover your Mac’s Data volume has run out of free space? A guide to working with snapshots, iCloud Drive, and other tricks to salvage your Mac. And how to prevent this from happening again.
The volume should only be half full, but installers and other software complains there’s insufficient free space. What to do.
With Apple’s SSD prices so high, you may for the first time have less internal storage in your new Mac than your old one. Tips to help you cope.
228.7 GB of my internal disk is occupied by ‘Other’. Where has this gone, and how can I reclaim it?
The Eclectic Light Company 