How to free up space on your Mac without guessing
When a Mac says the disk is almost full, the usual advice is to delete things until the warning goes away. It goes faster, and with fewer regrets, if you look at what is big before you delete anything.
1. See what is using the space
Open Apple menu, System Settings, General, Storage for the category view. It tells you that "System Data" is large, but not why. For a folder by folder breakdown, Vervain's Disk Analyzer shows a donut chart of your disk and a folder by folder breakdown.
2. Old installers
Disk images and installer packages pile up in Downloads: .dmg, .pkg and .iso files you used once. Sort Downloads by size in Finder and drag the ones you are done with to the Trash. Vervain lists installers older than 30 days in one place so you can review them together.
3. Caches and logs
Apps keep caches in ~/Library/Caches and rebuild them when needed, so clearing them is safe in principle, but it can make apps feel slow for a while. Clear the biggest ones rather than the whole folder. Vervain's System Junk groups caches, logs and browser caches and marks each item safe, review or risky.
4. Leftovers from apps you removed
Dragging an app to the Trash leaves its preferences, caches and support files behind in your Library folder. Vervain's App Uninstaller removes an app together with its leftovers, and the Leftovers screen finds data from apps that are already gone.
5. Large old files and duplicates
Movies, disk images and archives you have not opened in months are usually the quickest win. Vervain's Large and Old Files module lists big files you have not opened in a while, and Duplicates finds identical copies so you can keep one. If you do this by hand, check before you delete anything in Documents.
6. Developer leftovers
If you write code, build folders and downloaded models are often the biggest items on the disk. See the guides on old node_modules folders, Xcode caches and downloaded AI models.
7. Time Machine local snapshots
macOS keeps local snapshots when Time Machine is on and clears them by itself when it needs the room. Removing them takes administrator rights and cannot be undone, so Vervain only shows them and copies the exact tmutil command for you to run in Terminal. It never deletes them.
Empty the Trash at the end
Vervain moves what you pick to the Trash, so the space only comes back once you empty it. Look through the Trash one last time before you do.