How can I sync up the contents of separate hard drives?

My boss wants to know what his best option is in this situation:

He’s got an external drive that he sometimes uses with his laptop. Often the files that he saves to that drive, he wants to eventually have on his desktop machine too. Aside from copying the files directly every time, what’s the best way for him to “sync” the drives of these two machines so that the contents become the same (I’m sure there are issues to consider regarding latest versions of files, but I guess he wants both computers to always have the latest versions of files that have the same name).

I believe there is a way to do it built into Windows XP, but I’m not sure. Also, I’m interested if there is any third-party software available that can get this done easily (or easier than the XP way to do it). Thanks for any help.

Try looking at the more advanced options of XCopy or Robocopy. Alternatively, you can make a share and use Offline Files.

I set up a mapped drive letter and use XCOPY - works great. Here’s the example:

XCOPY X:*.* Z:\ /R /E /A /D

then do the same in reverse:

XCOPY Z:*.* X:\ /R /E /A /D

He’s not a “command-line” kind of guy, so the first two are out… how does the “offline files” thing work? The drives are not networked.

Danged ‘submit’ button bit me:

Anyway - drives X and Z (or whatever you choose) can be subdirectories that are mapped to a drive letter. In my instance, X = C:\USBDRIVECOPY and Z is the root of the USB drive.

I’m having difficulty doing this; XP seems to only allow me to map network folders to drive letters.

Danger! If you use XCOPY to back up your files, you may be courting disaster.
Read all about it…

In short, XCOPY regenerates short filenames, possibly doing something like this:

Folder “My Secretary’s Hot Photos” is originally mapped to “MYSECR~1”
Folder “My Secrets” is originally mapped to “MYSECR~2”
Your wife finds the hot photos and deletes the folder.

You now have this:
Folder “My Secrets” mapped to “MYSECR~2”

You then do a XCOPY to another drive, and XCOPY calmly does this:
Folder “My Secrets” mapped to “MYSECR~1”

Big deal, you say?

It is a very subtle bug that will bite you in the butt if you are dealing with folder names that find themselves in fancy MS registry entries in short format.
Go ahead, create a folder called “C:\Program A” and see what XCOPY does: it would probably change the all-important “Program Files” to be “PROGRA~2”, breaking a zillion things.

Sadly, many applications still use short filenames for command line stuff.

I use a great little program (It’s $10) called “CopyTo,” which can track whatever folders you want, and when you want to back up, it will scan the source drive and the destination drive, determine the differences and copy any new or updated files to the destination drive. I use this to backup My Documents, all my photos and my website. I just flip on my external HD, double click the CopyTo icon and it automatically updates. It gives you a list of the changes that will be made before it copies, so you can check if you want.

There are options to either 'copy new or updated files" which does what it says, replacing older files that are on the backup drive. You can also have it do that, but make backup copies of any of the updated files, so you never lose an older copy. You can also set it to syncronize, so it will delete any files on the backup drive that are no longer there on the source drive. You can change this option via a drag down menu at any time. You can also add any number of directories from any number of drives to copy to any other location. it’s really handy.

You can get a trial at, and then pay the $10 if you want to keep it.

CG: if the boss is not a command-line guy, you can place these command lines in a shortcut & all he has to do is click the shortcut.

Create a new shortcut and make the target “cmd.exe /c xcopy …”

As to mapping drive letters to folders on the same machine, you have to use the SUBST command-line command. And unlike network mappings, SUBST entries do not survive a reboot. But that’s easy to overcome by inserting “cmd.exe / c subst Z: C:\MySpecialFolder” into the registry as a startup item.

The concern about XCOPY as a backup tool mangling short filenames was legit & huge in the win95/98 days. Nowadays not so much, particularly for data files as opposed to installed program files & components. If your boss is still using Win-98 era software on his XP machine I’d be cautious. If not, not.

I use AJC Directory Synchronizer. It has the usual convenient options and also allows for the 1 hour variation that can occur between two computers due to Daylight Savings Time. It also allows for the 1-2 sec difference that seems to crop up occasionally between files located on multiple machines (wish I could figure out why that happens!).

What I would really like to find is a program that runs in the background that continually monitors and syncs two different drives. The problem with sync programs is that if you move a file to a different folder, you end up with a copy in each folder after the sync, a real nuisance.

Here is Microsoft’s take on it. I have used Briefcase which is built into XP. It is rather basic but I found it sufficient for keeping my laptop up-to-date with important files from my desktop.

I wouldn’t worry a bit about using XCOPY for data. I would choose another tool, however, to back up a full hard drive with applications or even the OS on it.