The following were suggested in response to a plea for software or services that would enable a Mac to do simple file synchronization to an external USB disk to act as a backup and file transport to and from a home office. The following are the suggestions and some opinions based on limited testing or notes by the people who suggested them.


The format for most of the items below are in the form: Name (#a/#b/#c) [cost, notes] Other notes.

The triplet of numbers are:

  • #a = number of people who suggested the item

  • #b = number of google pages referring to the product or service (very rough measure of popularity)

  • #c = number of google links to the home pages (ditto)

If you have further comments, personal reviews of the software, or pointers to relevant pages, please send them to me

1. Commercial, Cloud-based Backup and Restore Services

Google Trends measure for DropBox, CrashPlan, SugarSync.

1.1. DropBox

DropBox (4/7M/1370) [Free 2GB account, more storage for more $] Cloud Backup, restore, sync with any other internet-connected device. Cross-platform clients, Simplicity of operation, reliability. If you also add a MobileMe subscription ($100/yr), it addresses most of the Mac items that you might want to keep sync’ed. (see also iBackup below.

1.2. Crashplan

Crashplan (1/157K/97) [Free version with limited storage, $3.50/mo for unlimited storage for 1 computer $5/mo for family, can buy onsite, offsite server (but no easy access to cost for those services)] Cloud Backup and restore Encrypted data, continuous backup for $ version.

1.3. SugarSync

SugarSync (1/1M/277) Cloud sync utility. [30GB for $5/mo to 250GB for $25/mo]. Simplicity of operation, but reporting user had repeated problems with data reliability.

1.4. User Notes

With DropBox (not sure about CrashPlan) you have to alter your file structure to do a sync. Not so with SugarSync which adapts to your existing hierarchy. Some people have experimented with symlinks, but I don’t quite understand how that works (with Drop Box): possibly by putting their synced folders in the DB folder and sym linking out to their normal working directories. If you don’t want to mess with your file structure, DB is not a good option.

2. Native Mac Applications

Google Trends measure for ChronoSync, FileSync, Synchronize X, Super Flexible File Synchronizer.

2.1. Proprietary

2.1.1. ChronoSync

ChronoSync (1/71K/93) [$40 (but you’ll need to buy 2 copies to sync between them), volume discounts] Native Mac file sync utility. Can make bootable backups. Can’t operate with non-mounted disk tho. Looks very shiny, but it takes up 40MB(!) vs <1MB for Unison. However, it does work very well and it has a number of nice features (detected that the source and target differed in Cap-sensitivity, logging, rollbacks, etc.). Easy to set up. But, the demo is highly restricted, so I can’t tell if it works completely as advertised.

2.1.2. FileSync

FileSync (1/13.6K/2) [Free, not OSS] Fair number of feature and UI limitations. Not as flexible as unison. Did not test further.

2.1.3. SuperDuper

SuperDuper (2/184K/330) [Free restricted version, $28 for extended version] It’s a backup and restore utility rather than a file sync utility. can generate bootable backups. Very simple to use and quite reliable. Never had a dropped file or a crash.

2.1.4. Synchronize X

2.1.5. Super Flexible File Synchronizer

Super Flexible File Synchronizer (1/251K/35) [$60, volume discounts] Cross platform, many awards, lots of options, site-licensed by UCSC for $1200. Looks very spiffy, but didn’t have time to download to test yet.

2.1.6. iBackup

2.2. Open Source

2.2.1. arRsync

2.2.2. rsync

2.2.3. Unison