Settings & keep-time · Notifications
When does Storage Studio warn me that my Mac is low on space?
Short answer: By default it warns (orange icon) when free space on your built-in drive drops below 40 GB, and at critically low (red, below 15 GB) it notifies you and steps in automatically.
Storage Studio watches your built-in drive's free space. When it's getting low the menu bar icon shows an orange warning badge, and the Internal card's bar turns orange; when it's critically low the icon turns red, you get a notification, and Storage Studio steps in automatically to relocate items your rules allow.
By default "getting low" starts below 40 GB free and "critically low" below 15 GB. For ways to free space now, see freeing space.