Purgeable space is macOS's way of holding onto files it thinks it might need later—iCloud downloads, Time Machine local snapshots, cached data—while promising to evict them when your disk gets full. The problem is that promise sometimes breaks. You watch the grey bar sit there in Disk Utility, your free space stays stubbornly low, and no amount of waiting makes it budge. If purgeable space won't clear on your Mac even after you've tried the obvious steps, this guide works through the real culprits, from stuck APFS snapshots to Spotlight indexing loops.
Why Purgeable Space Gets Stuck
macOS marks space as purgeable rather than free so it can serve it up instantly when needed, without forcing you to re-download or regenerate content. Normally the OS flushes it automatically under disk pressure. When it doesn't, the usual suspects are:
- APFS local snapshots — Time Machine creates these frequently; they accumulate quietly and are the single most common cause of purgeable space that refuses to shrink.
- iCloud optimized storage — files marked for eviction but whose metadata hasn't fully synced.
- Spotlight re-indexing — a stuck or looping index job holds large temporary files open, blocking reclamation.
- Open file handles — an app is holding a cache file open, so the OS won't evict it.
- Sleep image / hibernation file — on some configurations this can bloat purgeable counts.
Fix 1: Check What's Actually Holding the Space
Before deleting anything, confirm the source. Open Terminal and run:
df -h /
Then compare with Disk Utility (Applications → Utilities → Disk Utility, select your volume, click Info). The gap between "Used" and "Available + Purgeable" tells you how much is genuinely stuck. You can also get a machine-readable breakdown with:
diskutil apfs list
Look for "Local Snapshots" under your APFS volume — if you see a long list, that's almost certainly your culprit.
If you'd rather skip the Terminal, Crumb's Visualize tab shows your disk map alongside a whole-Mac audit, so you can see purgeable, snapshots, and large cached items at a glance before deciding what to remove.
Fix 2: Delete APFS Local Snapshots (Most Effective)
Local Time Machine snapshots are the leading reason purgeable space is not clearing on Mac. List them:
tmutil listlocalsnapshots /
You'll see output like com.apple.TimeMachine.2025-11-03-142201.local. Delete individual ones:
tmutil deletelocalsnapshots 2025-11-03-142201
Or delete all local snapshots at once (safe if you have an external Time Machine backup):
sudo tmutil deletelocalsnapshots /
Risk note: Local snapshots are a safety net for recovering deleted files when your Time Machine drive isn't connected. Deleting them is permanent. If you have an up-to-date external backup, the risk is low.
Fix 3: Trigger Disk Pressure Artificially
macOS only releases purgeable data under disk pressure. You can nudge it by filling a temporary file and immediately removing it:
cd /tmp && dd if=/dev/zero of=pressurefill bs=1m count=10000; rm pressurefill
This writes roughly 10 GB, which should be enough to prompt the OS to flush cached/purgeable content. Watch Disk Utility refresh after you remove the file. Don't use a larger count than your actual free space allows.
Fix 4: Disable, Then Re-Enable iCloud Drive Optimization
If iCloud Optimized Storage is the source, toggling it forces a metadata sync that often unsticks the purgeable accounting. Go to System Settings → Apple ID → iCloud → iCloud Drive → Options and uncheck "Optimize Mac Storage." Wait 30 seconds, then re-enable it. Give it a few minutes; the purgeable number should drop.
Fix 5: Force a Spotlight Reindex
A runaway Spotlight index job can hold temporary files open indefinitely. Force a clean reindex:
sudo mdutil -E /
This erases and rebuilds the index for your startup volume. Spotlight search will be slow for 20–60 minutes while it rebuilds, but this clears any looping index processes. If purgeable space is stuck after other fixes, this is worth trying.
Fix 6: Clear System Caches and Logs Manually
System caches at ~/Library/Caches and logs at ~/Library/Logs and /var/log can contribute to purgeable totals. You can clear user caches with:
rm -rf ~/Library/Caches/*
Risk note: This is generally safe — macOS and apps rebuild their caches on next launch — but if an app is currently open, it may behave unexpectedly. Quit all apps first. Do not delete files inside /System/Library/Caches manually; those are managed by the OS.
System logs can be cleared with:
sudo rm -rf /var/log/*.log /var/log/asl/
Fix 7: Run First Aid in Disk Utility
Occasionally the APFS container's free-space accounting gets out of sync. Open Disk Utility, select your APFS container (the top-level item, not the volume), and click First Aid. This repairs the on-disk metadata without touching your files. If First Aid reports errors it can't fix, boot to Recovery Mode (hold Power on Apple Silicon or Cmd-R on Intel at startup) and run First Aid from there.
Fix 8: Remove the Sleep Image
On MacBooks configured for Safe Sleep (hibernation mode 3 or 25), macOS maintains a sleep image at /private/var/vm/sleepimage equal to your installed RAM. On a 32 GB Mac this is 32 GB that may count toward purgeable. Check:
ls -lh /private/var/vm/sleepimage
If you don't need hibernate (you're comfortable losing open apps on a full battery drain), you can disable it:
sudo pmset -a hibernatemode 0
sudo rm /private/var/vm/sleepimage
Risk note: Disabling hibernation means if your battery dies completely while in sleep, you lose any unsaved work. Not recommended for users who regularly run the battery down. Reverse with sudo pmset -a hibernatemode 3.
Fix 9: Use a Cleaner That Targets Purgeable Specifically
If you've worked through the list above and can't remove purgeable space because you're not sure what's safe, a purpose-built tool helps. Download Crumb and run a clean from the menu bar. Crumb targets System Data, caches, logs, and temp files with a single click, and its "Is this safe to delete?" AI explains any folder and its removal risk before you commit — useful when you're staring at an unfamiliar path and don't want to guess. It also surfaces large items and leftover app files that often inflate purgeable counts without being obvious in Finder.
Quick Reference: Purgeable Fixes by Cause
| Symptom | Likely cause | Fix |
|---|---|---|
| Large purgeable, Time Machine active | APFS local snapshots | Fix 2 — tmutil deletelocalsnapshots |
| Purgeable grows after iCloud sync | iCloud Optimized Storage | Fix 4 — toggle optimization off/on |
High CPU from mds_stores process |
Spotlight indexing loop | Fix 5 — mdutil -E / |
| Purgeable matches installed RAM | Sleep image | Fix 8 — disable hibernation |
| Purgeable unchanged after all fixes | APFS accounting bug | Fix 7 — Disk Utility First Aid |
A Note on Safety
Most of the steps above are recoverable or low-risk, but a few deserve a reminder: deleting local snapshots is permanent (keep an external backup), and disabling hibernation trades convenience for disk space. When in doubt, work from the top of this list — the safest fixes are first.
Conclusion
Purgeable space that refuses to clear is almost always snapshots, an iCloud sync stall, or a Spotlight index stuck in a loop — none of which macOS makes easy to diagnose. Work through these nine fixes in order and you should see the grey bar shrink. If you want a faster path and a visual overview of what's taking up space, Crumb gives you both without needing to open Terminal at all.