I know there is a similar topic on syncing between computers, but I'm looking for an application to run on one computer that will sync a "document/file" folder with a folder on my secondary/external USB drive.

What would be the best solution?

I know I could use Dropbox & Live Mesh, but they use up bandwith which isn't very good when I drop in a lot of large files.

I'm running Windows 7, but I assume any solution for Windows Vista would work just fine.

  • Ooh - good question. I'd be interested in Mac OSX Tiger/Leopard suggestions.
    – robsoft
    Jul 18, 2009 at 8:57
  • don't use the one that comes with it if you are using sandisk u3 usb drive. it is buggy...
    – kishore
    Jul 18, 2009 at 10:22
  • 2
    @robsoft I haven't tried it, but unison cis.upenn.edu/~bcpierce/unison looks like it may work for mac, haven't actually tried it though.
    – cobbal
    Jul 18, 2009 at 15:09
  • @cobbal - thanks for the suggestion, will go and take a look.
    – robsoft
    Jul 24, 2009 at 7:24

7 Answers 7


You could run a freeware synchronization program. I've used SyncBack (freeware) and I'm very happy with it. I use it to synchronize some folders to as NAS at home.

Screenshot Syncback freeware

  • Lol I already +1 you here ;-)
    – Ivo Flipse
    Jul 27, 2009 at 14:55
  • 4
    You probably shouldn't be hotlinking that image. Upload it to ImageShack.
    – MJeffryes
    Jul 31, 2009 at 10:30

I've used SyncToy from Microsoft in the past - although do note that version 2.0 does have issues with syncing to NAS devices.

  • Likewise. I use it to back up data between drives. Combine that with task scheduler to do automatic periodic backups. Jul 18, 2009 at 11:48
  • SyncToy worked well too, but I preferred SyncBack
    – Ivo Flipse
    Jul 22, 2009 at 7:47
  • Other bugs too. superuser.com/questions/13493/…
    – Will M
    Sep 5, 2009 at 15:30

I use Unison with Windows/Cygwin as well as with OSX. SyncBack is a pretty good choice for windows though.

  • 1
    Unison is great. Been using it for years. Readers should note that Cygwin is not necessary to use Unison on Windows.
    – dggoldst
    Aug 10, 2009 at 20:53

By the look of the work you're doing, I might suggest setting up something like Subversion to do this for you. There are good clients for Windows available, and binaries for the server (and I use the term loosely).

Generally thought of as "for programmers", Subversion (or version control in general) is an amazing tool for managing any kind of document.

Advantages to version control for documents

  1. Easy sync.
    • Version control is designed for developers to easily work on the same set of documents, and keep them all up to date. These design considerations will help you keep your external hard drive, multiple PC's, etc, up to date.
    • If you find the use for it, you can even access your documents via the internet and no longer need to sync to a hard drive.
  2. Control.
    • Version controlled documents can be locked from changes.
    • You can lock people out of changing your documents by only granting them read permission.
  3. Revert.
    • Ever deleted a paragraph only to find you need it three weeks later? Version control can easily revert back to an older version of the document.
  4. Collaboration (related to #1).
    • Share your documents with many users, easily kept up to date with the latest copy.
    • Keep track of who made changes via the check-in log.

Just wanted to toss out an alternative approach, instead of just alternative software.

  • Subversion (personally I prefer Mercurial) is fantastic for documents you are working on and actively maintaining. It works much less well for just synching arbitrary folders with files you are not actively changing or maintianing. I love Mercurial for programming and even for more traditional writing. I would not use it to maintain my MP3 collection or even a collection of pictures of my kids. Nov 7, 2011 at 22:05

I agree with Ivo, SyncBack is really a great program. Before that I was happily using Second Copy, which works very well also. Note that SC has a free trial and costs $29.95 for the full version.


WinMerge could also do the trick.


Allway Sync is a tool that does this.

Short description:

It uses innovative synchronization algorithms to synchronize your data between desktop PCs, laptops, USB drives, remote FTP/SFTP servers, different online data storages and more. Encrypted archives are supported. Allway Sync combines bulletproof reliability with extremely easy-to-use interface.

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