Back That Data Up
Backup vs sync
iCloud and Dropbox are sync, not backup.
They keep your files the same everywhere. A backup keeps yesterday around, so when something goes wrong you can go get it.
What sync does
A mirror for every device
Dropbox, iCloud Drive, Google Drive, and OneDrive copy your files so every device shows the same thing. That is great for working across machines. Open a document on your Mac, pick it up on your iPad, finish it on a Windows laptop. Sync is genuinely useful at that job.
But it is a mirror. Delete a file and the mirror copies that deletion everywhere. Let an app corrupt a document and the corrupted version overwrites the good one on every device. Let ransomware rewrite your files with encrypted garbage and the sync service faithfully copies the garbage to the cloud. By the time you notice what happened, the good versions are gone.
Most sync services keep a short version history (30 days is common). That sounds like a safety net, but it is not the same as a backup. Version history is per file. Restore a whole folder is clunky. Restore a whole Mac from a ransomware event is not something Dropbox was built to do.
What a backup does
A full copy of yesterday, still here today
A backup keeps point in time copies. Yesterday is still there. Last Tuesday is still there. The version from the morning before the ransomware hit is still there. When the bad day comes, you open the backup from before it happened and pull your files back.
Good backup software writes every snapshot as a full browsable copy of your Mac. You open a window that looks exactly like your disk looked on that day, navigate to the file you need, and drag it out. No special restore wizard. No decryption password you have to remember separately. Just your files, organized the way you left them.
The reason this is possible without consuming hundreds of gigabytes per snapshot: files that have not changed between snapshots are hardlinked. They point to the same data on disk. Each snapshot is independent and fully readable, but only changed files take up new space. You get the full picture of every day without paying for it 365 times over.
The honest comparison
What each one actually gives you
| Sync | Backup | |
|---|---|---|
| Keeps old versions of files | ✕ | ✓ |
| Survives accidental deletion | ✕ | ✓ |
| Survives ransomware | ✕ | ✓ |
| Lets you restore a whole Mac | ✕ | ✓ |
✓ yes · ✕ no. Sync is genuinely good at keeping files in sync across devices. That is a different job than backup.
Common confusion
"But my files are in iCloud, so I'm backed up"
This is the most expensive misunderstanding in Mac ownership. iCloud Drive is sync. It does not back up your Mac. It copies certain folders to Apple's servers so they match on your other devices. If you delete those files, iCloud deletes them everywhere.
There is also a separate service called iCloud Backup, which backs up your iPhone and iPad. Your Mac is not covered by it. A lot of people assume it is.
The tell is simple: if you deleted a file from your desktop right now and then opened iCloud.com, would you be able to get it back? The honest answer for most people is: maybe, for 30 days, if the file was inside an iCloud synced folder. Your Desktop and Downloads are not always synced. Your apps, preferences, and system state are not backed up at all.
That is the gap. A backup covers the whole Mac. It keeps every version. And when the bad day comes, you restore to the exact state things were in, not a subset of your most recently synced files.
Back That Data Up
Real backups. Your own cloud. One time price.
The thing I am most proud of in Back That Data Up: you can lock your backup so it only opens with a FIDO hardware key, a physical token like a Yubikey in your USB port. No other major Mac backup app does this. It means the backup is sealed against anyone who does not have both your Mac and the key in their hand. A password can be guessed or shared. The key has to be physically present.
It can also use the cloud storage you already pay for. Cloud Vault encrypts your most important files into a private format that only your Mac can open, then stores them in Dropbox, Google Drive, iCloud Drive, or OneDrive as versioned backups. That is not sync. It is a proper offsite backup copy, encrypted before it ever leaves your machine, stored in your own account.
Back That Data Up gives you real point in time backups. Every snapshot is a full browsable copy of your Mac as it existed at that moment. Unchanged files between snapshots are hardlinked so the whole library writes in seconds, but each snapshot is independent and fully readable without depending on any other snapshot in the chain.
I built BTDU because I wanted one app that just always runs in the background for my partner, who will never open settings, and still gives me everything I want to tweak. Same binary. No subscription. Backup and Cloud Vault included in the one time purchase.
Hardware key unlock
Lock your backup with a FIDO key such as a Yubikey. No other major Mac backup app does this. The backup stays sealed without the physical token.
One time price
Personal $29.99, Family $49.99. No subscription. Old school software: you buy it, you own it. Bug fixes and minor updates are free for the life of the major version.
Cloud Vault built in
Encrypted backup to Dropbox, Google Drive, iCloud Drive, or OneDrive. Your own cloud account. Private format only your Mac can open.
The honest answer
Do you need sync, backup, or both?
You probably need both. They do different things.
Sync is for working across devices. If you want to start something on your Mac and finish it on your iPad, sync is how you do that. iCloud Drive, Dropbox, and Google Drive are all excellent at this. Keep using them for this.
Backup is for when something goes wrong. Your Mac is stolen. Your drive fails. Ransomware rewrites your files. You delete something you needed. Backup is the safety net that means those events are recoverable rather than permanent.
The people who get hurt are the ones who have sync but believe they have backup. When the bad day comes, they find out the difference the hard way.
If BTDU sounds like a fit for what you need, here is where to start. $29.99, one time. No subscription, ever.
Already using iCloud Drive or Dropbox? Good. BTDU runs alongside them. Sync and backup are not competing for the same job.