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Clone a Volume with Apple Software Restore (asr)

Duplicate an entire macOS volume to another disk block-for-block with the built-in asr tool.

macOSbackupcloneasrMedium risk
Run `sudo asr restore --source <volume> --target <volume> --erase --verify` to clone a volume.

01Command

Command
$ sudo asr restore --source /Volumes/Macintosh\ HD --target /Volumes/Clone --erase

02What it does

asr is Apple's volume duplication engine: it copies the source volume to the target, erasing it first with --erase, and verifies every block unless you pass --noverify. The result is a bootable clone when the source is a bootable system volume. It requires the target to be at least as large as the data being copied, and works with APFS volumes on modern macOS.

03Risk

RiskMedium risk
RequirementsA target volume large enough to hold the source data.
!Warning: The --erase flag wipes the destination — asr will not warn if you point it at the wrong disk.

04Undo

✓No undo needed — this command does not change persistent state.

05Sources

  • ASR command: Copy volumes in macOS
    SS64 · technical · 2026-09-17
    Evidence: Documents asr restore with --source, --target, --erase, --verify, and --noverify options for volume duplication.

Last verified: 2026-09-17 · Category: System & Settings

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