iCloud & iCloud Photos · iCloud storage space and plans
What's the difference between "iCloud storage is full" and "Mac storage is full"?
Short answer: They're separate: iCloud storage is your online Apple Account space (photos, Drive, backups, Mail); Mac storage is your Mac's disk. Freeing one doesn't free the other. Fix iCloud full in iCloud; fix Mac full on the Mac — Storage Studio works on the Mac side.
They're two separate pools of space. iCloud storage is the space in your Apple Account online, shared by your photos, iCloud Drive, device backups, Mail and messages. Mac storage is your Mac's own disk. Filling one doesn't fill the other, and freeing one doesn't free the other.
- "iCloud storage is full" — fix it in iCloud: delete or move things out of iCloud, or change your plan. See what to do when iCloud is full.
- "Mac storage is full" — free space on the Mac: clear caches, make cloud files online-only, move big items to an external drive.
They interact in one way: with Optimize Mac Storage, iCloud keeps files online to save Mac space — but that needs iCloud space to hold them. Storage Studio works on the Mac side; it never deletes from your iCloud account.