Offline drive catalog guide
How to catalog external hard drives offline on Mac
An offline drive catalog is useful only when it tells you what was actually observed, where the physical disk lives and which areas were not safely readable. Start with one explicit source and preserve that boundary.
1. Give the physical drive a stable home
Label the case and record a shelf, cabinet, drawer or box before scanning. A file result is much more useful when it leads to a precise physical location instead of another pile of disks.
2. Approve one mounted source
Choose the external volume or a specific folder on it. Inventory regular files by relative path, size and modification time. Never follow symbolic links beyond that approved root, and do not descend into app or library packages by default.
3. Keep skipped evidence visible
Record unreadable directories, symbolic links, packages, unsupported entries and unavailable optional hashes. A catalog with explicit boundaries is more trustworthy than a higher file count with silent omissions.
4. Save an immutable local snapshot
Sort the entries, include scan issues, and calculate a digest for the snapshot. Search that saved evidence after the drive is ejected instead of requiring every disk to stay mounted.