What is System Data on a Mac, and can you delete it?
System Data is the part of the Storage screen that holds files macOS cannot put in a more specific category. Apple describes it as a general category for Apple and third party files that do not fit elsewhere. A big System Data number does not mean macOS itself is big. It usually means caches, logs and local backups.
Where to see it
Open the Apple menu, choose System Settings, click General, then Storage. System Data appears in the list and as a part of the bar. On macOS versions before Ventura 13 it may be labelled Other, and you reach it from About This Mac, then Storage.
What is usually inside
From the Mac checked for the blog post free up space without a cleaner on 7 October 2026, System Data typically holds:
- caches that apps keep so they start faster
- logs
- local Time Machine snapshots
- virtual machine images
- files from apps that do not say what they are
Your Mac may hold different things. The category is a catch all, so there is no single list.
Can you delete it?
Not as one block. You cannot select System Data and press delete, and you should not try to remove system folders. What you can do is inspect the pieces that are yours:
- Look at the size of your Library folder’s Caches with the commands in find large files on a Mac.
- Clear single app caches carefully, as shown in clear caches safely.
- Leave local Time Machine snapshots alone unless you need space right now. The blog post notes macOS removes them itself when space gets low.
Why it keeps growing
Caches and logs grow with use. Developer tools, video editing and virtual machines add large files that land here. If it grows fast, find which folder is growing rather than guessing.
Restarting and Safe Mode
Apple says starting in Safe Mode clears certain system caches, which can free enough space for a task like a macOS update. Restart normally to leave Safe Mode. Apple’s page does not promise this will shrink System Data.
A way to look
NotchStar’s Disk tool ranks folders in your home folder by size and scans caches, logs and Xcode build data. Every item it removes goes to the Trash first.
