A computer feature or peripheral that has completely stopped should be separated into driver, permission and physical-connection layers before assuming component failure. For Mac Time Machine backup, first open the latest backup, inspect the exact error and run First Aid on a directly attached disk.
What this covers
- Mac Time Machine backup with this exact failure state
- Diagnosis across destination disk/network versus source errors, encryption, permissions and space
What it does not cover
Try in this order
0 of 4 completedCapture the exact failure state
ReversibleCheck Device Manager or System Information for whether the hardware is even detected, and whether an error code is shown. Expected behavior: complete incremental backups to the selected healthy destination.
Isolate the component boundary
ReversibleOpen the latest backup, inspect the exact error and run First Aid on a directly attached disk. Test the peripheral on a different port or user account, and test a different peripheral on the same port. Boundary to separate: destination disk/network versus source errors, encryption, permissions and space.
Correct only the proven cause
ReversibleReplace the failed cable/disk or create a new backup set after preserving the old one. Reinstall or roll back the driver, or grant the missing app permission.
Verify and stop safely
ReversibleConfirm the feature works after a full restart in at least two different applications. Do not erase the only backup or ignore storage-health errors.
Evidence ledger
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