Guide · 5 min read

“Your startup disk is almost full” - how to fix it on a Mac

The “Your startup disk is almost full” warning means your Mac's boot drive is nearly out of space, which can slow things down and block updates. Here's how to fix it fast, biggest wins first.

1. Find the biggest offenders first

Don't delete randomly. Use a disk map to see your largest folders, or check System Settings → General → Storage for a rough split.

2. Clear the quick wins

Empty the Trash
Clear app caches in ~/Library/Caches
Delete large files in Downloads and Movies (old videos, disk images, VMs)
Remove duplicate files

3. Reclaim hidden space

Local Time Machine snapshots (the “purgeable” space)
Old iOS device backups
App leftovers from apps you've deleted
Developer build folders (node_modules, DerivedData)

Tip: If you're critically low, restart your Mac first - it lets macOS purge some space automatically and can clear the warning long enough to work.

4. Do it all at once with TidyBar

TidyBar scans every one of these categories together, shows what's reclaimable for free, and clears it to the Trash in one click - the fastest way out of a full startup disk without guessing what's safe to delete.

FAQ

Why is my startup disk full?+

Usually a mix of caches, large media files, duplicates, local snapshots, app leftovers and (for developers) build artifacts that built up over time.

What should I delete first?+

Start with the Trash, caches and the largest files - they give the most space back for the least risk. Everything TidyBar removes goes to the Trash, so it's recoverable.

Do it all in one click with TidyBar

Scan free to see what you can reclaim. $25 one-time · no subscription.

Download TidyBar

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