Full Restore from TimeMachine

Phase 1: Access Recovery and Erase the Broken Disk

  1. Connect Both Drives: Plug in your Time Machine backup disk and the USB installer drive (if you used one for the failed upgrade).
  2. Access Recovery Mode:
    • Intel Macs: Restart your Mac and immediately press and hold Command (⌘) + R until you see the Apple logo or a spinning globe.
    • Apple Silicon Macs: Press and hold the Power button until you see the startup options screen, then select Options and click Continue.
  3. Open Disk Utility: From the macOS Utilities window, select Disk Utility and click Continue.
  4. Erase the Internal Disk:
    • Go to View > Show All Devices.
    • Select the top-level physical device of your internal Mac drive (e.g., APPLE SSD…).
    • Click Erase.
    • Name: Macintosh HD
    • Format: APFS
    • Scheme: GUID Partition Map
    • Click Erase to wipe the broken Sequoia installation.
  5. Quit Disk Utility: Close Disk Utility to return to the macOS Utilities window.

Phase 2: Restore from Time Machine Backup

  1. Start Restore: Back in the macOS Utilities window, select Restore From Time Machine (or „Restore from a Time Machine Backup“) and click Continue.
  2. Select Source: Click Continue again and select your Time Machine Backup Disk from the list of available sources.
  3. Select Backup: You will see a list of backup dates. Select the most recent backup of your working Ventura system (the backup before you attempted the upgrade).
  4. Select Destination: Select the internal drive you just erased (Macintosh HD) as the destination.
  5. Start Restore: Click Restore and wait for the process to complete. This can take several hours depending on the size of your data.