How to catalog your external hard drives on a Mac

A disk catalog is a list of what is on each of your drives, kept somewhere that does not depend on the drive being plugged in. Photographers, video editors and archivists have been keeping them for decades, usually in a spreadsheet. The idea is simple. Keeping one current is the hard part.

Why you need one at all

Your Mac only knows about the drives that are connected right now. Spotlight keeps each drive's index on the drive itself, so eject one and its files vanish from search. If you own more than two or three drives and most of them live in a drawer, the question "which drive is that file on?" has no answer without a catalog.

The manual ways

A file listing per drive

Open Terminal, then list everything on a drive into a text file you keep on your Mac:

find /Volumes/DriveName > ~/Documents/DriveName.txt

Do that for each drive and you can search every listing at once with Spotlight or a text editor. It is free and it works. It records only names and paths, though, and the moment you change anything on the drive, the listing is out of date until you run it again.

A spreadsheet

Many archives are a spreadsheet with a row per project: which drive, what is on it, where the drive lives. It is readable and portable, and it is only as accurate as the last time someone updated it by hand. It also tends to track projects, not files, so it helps you find the drive and not the file on it.

Labels on the drives

Tape on the case, a date range, a client name. Worth doing regardless, and hopeless on its own the first time a project spans two drives.

Every good answer here is a catalog. They fail because keeping one by hand is work nobody keeps up.

What a catalog should do for you

If you are choosing a tool, or building a habit, these are the parts that matter:

• It stays on your Mac. Otherwise it disappears with the drive, which defeats the point.
• It updates itself. A catalog you have to remember to refresh will be wrong exactly when you need it.
• It knows drives by identity, not name. People rename drives. Two drives called Untitled are not the same drive.
• It records where each drive is kept. Knowing the file is on Archive 04 only helps if you know where Archive 04 is.
• It can show you what you would get back. Thumbnails and details for files on an unplugged drive, so you plug in the right one first time.

Cataloging drives with GetFerret

GetFerret is built around keeping that catalog for you. Cataloging a drive is what we call burrowing it, and all your cataloged drives together make up the Warren, one list you can search whether a drive is connected or not.

• Plug in an external drive while GetFerret is running and it catalogs the drive automatically. The Drives window has a button to catalog every connected drive at once.
• Your Mac and network drives too. Catalog this Mac, or pick any drive or folder, including a NAS or a network share.
• Drives are recognised by identity, so renaming a disk does not break its catalog, its tags or your notes on its files.
• When you unplug a drive, GetFerret asks where you are storing it. Type "top desk drawer" once, and later a search tells you which drawer to open.
• Files on unplugged drives keep their thumbnails and details, so you can check you have the right one before you go and find the drive.

Everything stays on your Mac. The catalog is yours, and nothing about your files is sent to us.

The short version

A catalog is the only way to search drives that are not plugged in, and the only catalog that stays accurate is one that updates itself. Start with a text listing if you want to try the idea for free. When keeping it current becomes a chore, let an app do it.