Mac storage and SSD — full disk, can't install apps and slow SSD
Last updated:
Quick answer
SSD problems on a Mac fall into three categories: lack of space (always solvable through cleanup), file system corruption (Disk Utility First Aid), and hardware failure. On Intel Macs before T2 (2012-2017) we can clone data out of failing drives with specialist tools. On Intel with T2 (2018+) and Apple Silicon, the SSD is encrypted by the Secure Enclave, so instead we restore the logic board to a state where the T2/M-processor can again access and decrypt the SSD.
Alle spørgsmål
Why is my Mac disk full?
Check: Apple menu → About This Mac → More Info → Storage → Manage. Storage Management shows what's using the space. Biggest culprits: Photos library (local + iCloud), Mail attachments, the Downloads folder, old iOS backups, Time Machine snapshots. Delete or move them to an external disk.
Why does my Mac say "startup disk full"?
macOS needs at least 5-10 GB of free space to function. When the SSD is over 95% full, the system can no longer write cache and becomes extremely slow. Delete large files, empty the Trash, remove old iOS backups (Finder → your device → Manage Backups). Aim to keep at least 15% free.
Why can't I install apps?
If App Store or .dmg installation fails: 1) check disk space — you need 2-3x the app size free, 2) sign out and back into the App Store, 3) run 'Install' with your admin password, 4) check Gatekeeper in System Settings → Security. If the error mentions 'corrupt', the installer didn't download fully.
Why is the SSD slow?
Apple Silicon Macs typically run at 3000-7000 MB/s SSD speeds. If yours feels slow: 1) check SMART status in Disk Utility. 2) On the 256 GB Air M2 the SSD is only 1500 MB/s due to a single NAND chip — that's by design. 3) A near-full SSD slows down once it reaches 90%+. 4) A faulty SSD controller — contact us.
Why can't I delete files?
1) Make sure you're an admin user. 2) The file may be locked (Cmd+I → Locked). 3) An app may have the file open — close apps and try again. 4) If the entire Trash won't empty, try 'Empty Trash Securely' or boot into Recovery and use Disk Utility. 5) Permission errors are often fixed with Disk Utility First Aid.
Why can't my Mac boot from the disk?
If you see a folder with a question mark on startup: 1) boot into Recovery (Cmd+R / hold the power button) → Disk Utility → First Aid. 2) Test by booting from an external USB. 3) On Intel Macs before T2 (2012-2017) we can swap a socketed SSD or clone data out of the failing drive with specialist tools. 4) On T2 Intel (2018+) and Apple Silicon we restore the logic board to a state where the T2/M-processor can again access and decrypt the SSD (DKK 4,000-8,000). If the T2/M-chip itself is physically damaged, however, the data is lost.