Deep traversal

14.  Deep traversal scans.  Normally, Time Machine uses the FSEvents system or snapshots (APFS only) to save it having to scan your entire disk to discover what has changed since its last backup. Sometimes it cannot do that, and performs a deep traversal scan on the backup source. This is  explained here .

If T2M2 detects that one or more deep traversal scans have taken place, the following will be reported:

started 1 deep traversal scans,

completed 1 deep traversal scans,

These are not necessarily a bad sign - they do occur periodically anyway - but should alert you to potential problems. Repeatedly performing deep traversal scans is a bad sign, and should be followed up as explained. In Catalina, deep scans are just another of its repertoire of available techniques, and aren’t reported separately. However, they are included in the detailed breakdown of volume backups.

Compaction

Interpret result

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