How to Create and Manage APFS Snapshots Manually with tmutil

APFS snapshots aren’t exclusive to Time Machine’s automatic scheduling — tmutil also supports creating and managing them directly, useful as a quick, space-efficient safety net before a risky change, independent of your regular backup schedule.

Step 1: create a manual snapshot of the current disk state

sudo tmutil snapshot

This creates a local APFS snapshot immediately, capturing the current state of your disk — the operation completes almost instantly regardless of how much data is on the disk, since APFS snapshots are copy-on-write and don’t duplicate any data upfront.

Step 2: list existing local snapshots

tmutil listlocalsnapshots /

This shows every local snapshot currently retained, including ones created automatically by Time Machine’s normal background scheduling, not just ones you created manually.

Step 3: mount a snapshot to browse its contents directly

sudo tmutil mountsnapshot / -m /Volumes/SnapshotView

This mounts the specified snapshot as a read-only volume you can browse in Finder or Terminal, letting you inspect exactly what a file or folder looked like at that specific point in time, without needing to go through the full Time Machine restore interface.

Step 4: compare a file’s current state against the snapshot version

diff /Volumes/SnapshotView/Users/you/somefile.txt ~/somefile.txt

Useful for confirming exactly what changed in a specific file since the snapshot was taken, before deciding whether to restore it.

Step 5: unmount the snapshot when done browsing it

sudo tmutil unmountsnapshot / -m /Volumes/SnapshotView

Step 6: delete a specific snapshot manually

tmutil deletelocalsnapshots <snapshot-date>

The date argument matches the format shown in listlocalsnapshots output — useful for reclaiming space from a manual snapshot you no longer need, without waiting for macOS’s automatic thinning to eventually remove it.

Step 7: understand automatic thinning behavior

macOS automatically manages local snapshot storage under normal conditions — thinning older snapshots as disk space is needed elsewhere, without any action required from you. Manual snapshots you create are subject to this same automatic management, meaning a manually-created snapshot isn’t necessarily permanent; it’s still eligible for automatic removal under disk-space pressure, the same as an automatically-created one.

Step 8: use this as a quick pre-change safety net

sudo tmutil snapshot   # immediately before a risky system change
# ... make the change ...
# if something goes wrong, mount the snapshot (Step 3) to recover
# specific files, or use Time Machine's own restore interface for
# a more complete rollback

Why this is a meaningfully lighter-weight safety net than a full backup

A manual snapshot costs essentially nothing to create and takes effect instantly, unlike waiting for or triggering a full Time Machine backup to an external destination — making it a genuinely practical “just in case” step immediately before a risky change (a system update, a risky configuration edit, a large file operation) where a few seconds of overhead is worth having a rollback point available, even though it isn’t a substitute for genuine off-disk backups protecting against actual disk failure or loss.