Frequently asked questions

The fewer layers between your Mac and the storage, the more reliable the backup. Write. Directly. To. The. Drive. No disk images, no foreign file systems with a special driver in the middle. A single bad sector probably won’t take out a real drive—but it can destroy a whole image, and everything inside it, at once. The more direct the copy, the better the odds of it surviving intact when something goes wrong.

And something always goes wrong.

Time Machine is genuinely useful; pulling back a file from three weeks ago is worth having. But know what it is: not a copy of your Mac, but a versioned database layered on top of fragile file system features. That’s more moving parts, and every part is a place trouble can hide.

A direct copy is the opposite. It’s your whole drive, sitting there in the same format. Restoring is just copying it back: fast, complete, and if you only need one file, you can grab it in the Finder. And if you ever need to, you can often boot straight from the backup and keep working—a nice bonus.

When your backup drive goes bad, you might lose a file or two. But when a database backup goes bad, it often can’t be repaired, only replaced: the dreaded “Time Machine must create a new backup for you” means your entire history just evaporated.

Keep Time Machine. Just don’t make the fragile one the one copy you’re counting on.

Storing several backups on one drive? Format it as APFS and give each source its own destination volume. Every individual volume in an APFS container shares free space, and the system manages it intelligently. Don’t reach for disk images to “save space” (an image needs room to grow to its full size no matter what; hem it in and you’ll likely corrupt it and lose everything inside) and don’t use folders when you don’t have to: Apple tools like Migration Assistant won’t look in a folder.

Except in a pinch, never keep a backup on a volume that also holds the only copy of anything you care about, like a photo library or a document archive. Those need backing up too, and if one drive dies it shouldn’t take out both the backup and the only copy of your originals.

Keep the archive. Keep it separate. And back it up.

Your Mac’s internal drive probably isn’t where your biggest, most irreplaceable data lives. Photographers keep Lightroom libraries on external drives. Video projects, music, and photo archives spill onto them too. Those are easy to forget, precisely because they aren’t “on the Mac”—right up until the external dies and takes years of work with it. If it matters, it gets backed up, wherever it lives.

And here’s another part people miss: SuperDuper! doesn’t only copy whole drives. It copies—and keeps updated—individual files and folders, too.

Select that Lightroom library on your external and it maintains a current, ready-to-use copy on another drive, refreshed in minutes with Smart Update. Not an image to unpack, not an archive to restore: a real, live copy of exactly what you’d need in an emergency.

A network backup is fine as a secondary—never as your only one. By its very nature it’s the least reliable mechanism, because there are the most layers between you and your data: the network itself, the protocols, sleep and disconnects, other users.

SuperDuper! 4 can write directly to folders on a network drive, which is great as a second line of defense. Just don’t let it be your first.

More copies only help if they can’t all fail the same way. Two Time Machine drives feel like insurance—but if the problem is Time Machine, or the corner of APFS it depends on, both copies have it. You haven’t hedged; you’ve placed the same bet twice.

Real redundancy means different mechanisms: a direct clone and Time Machine and an offsite or cloud copy, so no single flaw can reach all of them.

(And yes—I make one of these tools, and yes, this is partly a sales pitch. But I wrote SuperDuper because I care, and it’s true to boot, which is why I run Time Machine and Backblaze right alongside SuperDuper!. Never lean on a single device or a single program. Even mine.)

It’s not enough for a backup to run; you have to know it worked. If a file can’t be read, you want to be told—now, while you can still do something about it. SuperDuper! reports it. Time Machine quietly moves on, and you find out the day you go looking for that file. A backup that fails silently is worse than one that fails loudly, because it sells you the calm without the coverage.