Organising files

One library from many machines

Updated 2026-07-31 · 4 min read

Years of Macs leave your files in layers. Merging them well is mostly about not making duplicates.

The situation

Files spread across a current Mac, an old Mac, a couple of Time Machine drives, and a cloud folder or two. The goal is one authoritative library; the risk is ending with three copies of everything and no idea which is current.

Gather in one place first

Pick the machine with the most disk and pull everything to a staging area — one folder per source, kept separate initially:

~/Consolidation/
  current-mac/
  old-macbook/
  backup-2022/
  dropbox-dump/

Copy, never move, from originals until the merge is verified. Keep the sources intact as a safety net.

Merge with duplicate awareness

Merge one source at a time into a growing "Master", checking for duplicates as you go rather than at the end. rsync with a dry run shows what each source would add:

rsync -avn ~/Consolidation/old-macbook/ ~/Master/

Files it would copy are genuinely new; the rest already exist. Then merge for real without -n.

Find the true duplicates

After merging, hunt byte-identical copies (the duplicate-files article's hash method) and same-name-different-content collisions. The second category is the dangerous one — two budget.xlsx files that are different versions, not duplicates. Compare dates and sizes before deleting either.

A filename index that shows every copy of a name across the whole staging area — same-size matches flagged — turns this from an afternoon into minutes, which is much of the case for having one.

Newest-wins, carefully

Where the same file exists in several sources, the most recent modification date is usually authoritative — but "usually" is why you verify rather than automate. rsync -u keeps the newer of two, which is the safe default for the bulk, with manual review for anything that matters.

Then, and only then, delete the sources

Once the Master is verified — counts checked, key files opened, a backup made of the Master itself — the staging sources and old drives can go. Not before. The merge that deleted the sources first is the one that lost the file.

Common questions

How do I merge files from several Macs without duplicating everything?

Stage each source separately, merge one at a time with rsync dry runs to see what is genuinely new, then hunt duplicates by hash before deleting any source.

How do I handle two versions of the same file when merging?

Compare dates and sizes — newest modification usually wins, but verify manually for anything important rather than auto-overwriting.