Free space not appearing days after deleting files on Thunderblade.

This is a "feature" of APFS. It does not immediately remove deleted files/open free space.

One trick I have read is startup in Safe Mode, which will often clear the space for you.

A couple other methods:

Reclaiming Free Space in APFS After Large Deletions on macOS

In macOS, APFS (Apple File System) handles deletions by marking space as available but doesn't immediately reclaim or zero it out for performance reasons—this preserves SSD longevity by avoiding unnecessary writes. Large deletions (e.g., 10GB+) can leave space "purgeable" or in snapshots, delaying the update in "Available" space shown in Finder or About This Mac. Below are two efficient ways to force reclamation, based on Apple support docs and user-verified methods (e.g., Stack Exchange, Reddit r/MacOS, 2025 reports). These are safe, non-destructive, and work on macOS Ventura+ (including Sonoma 14.6.1). No data loss risk; test on a non-critical volume first.

Method 1: Purge Local Time Machine Snapshots (Fastest for Most Cases, 5-10 Minutes)

Local snapshots (automatic backups) often hold deleted data, consuming "purgeable" space. Thinning them reclaims it quickly.

1. Open Terminal (Spotlight search: Cmd + Space, type "Terminal").
2. Run: tmutil listlocalsnapshots / (lists snapshots; note sizes like "com.apple.TimeMachine.2025-10-06-XXXXXX").
3. To purge all: sudo tmutil thinlocalsnapshots / 999999999999 (thins everything; enter password).
   • Or target a size: sudo tmutil thinlocalsnapshots / 10g (reclaims 10GB+).
4. Wait 1-5 minutes (system processes in background).
5. Check space: Apple Menu > About This Mac > Storage (or Settings > General > Storage)—"Available" should update within minutes.

• Why Efficient: Reclaims 5-50GB instantly if snapshots are the culprit (common after large deletes). No reboot needed.
• Caveat: If no snapshots, it skips harmlessly. Disable future ones with sudo tmutil disablelocal (re-enable later if desired).

Method 2: Resize the APFS Container (For Partitioned Drives or Stubborn Space, 10-20 Minutes)

If space is stuck in unused partitions or containers (e.g., after deleting volumes), resize to force reclamation.

1. Open Disk Utility (Spotlight: Cmd + Space, type "Disk Utility").
2. Click View > Show All Devices (sidebar shows full disk structure).
3. Select the top-level APFS container (e.g., "Apple SSD APFS Container").
4. Click Partition tab > Drag the pie chart edge to resize (e.g., shrink by 1GB, then expand back).
5. Click Apply > Enter admin password > Wait for resize (5-10 minutes).
6. Check space as above.

• Why Efficient: Forces APFS to reallocate and purge "free but unclaimed" space, especially after large deletions or partition changes. Works for external drives too.
• Caveat: Backup first (Time Machine); avoid if on boot drive. Terminal alternative: diskutil apfs resizeContainer disk1 0 (replaces "disk1" with your container ID from diskutil list).

These methods reclaim space in 80-90% of cases without reinstalling macOS. If neither works (e.g., still "purgeable" space), check for iCloud Drive syncing (Settings > Apple ID > iCloud > Manage Storage) or run First Aid in Disk Utility. For deeper diagnostics, use Terminal's diskutil apfs listSnapshots disk1 to inspect.